Protestant writer C. Michael Patton observed (without himself believing this):
Historic Protestantism has often charged the Catholic church with idolatry, believing that they have turned God into an idol of bread and wine, worshiping the elements without, indeed, contrary to, a scriptural basis.
This is an utterly wrongheaded criticism, as I have often argued, since idolatry, by definition, is a matter of the heart and interior disposition. No minimally informed Catholic has ever worshiped mere bread and wine (just as none have been dumb and absurd enough to actually venerate plaster in the form of a statue of a saint). We are worshiping Jesus Christ present in what was formerly bread and wine.
Obviously, other Christians may deny the fact of what we believe in faith to be taking place, but whatever the Mass is, it is not idolatry, which is worship of what is not God and raising something other than God to His sole place of supreme exaltation.
Clearly, Catholics aren’t doing that, which is simple to see in the literal meaning of the word transubstantiation: “change of substance.” Think about it for a moment in this light: how does the following “logic” of our anti-Catholic critics make any sense?
1) Catholics believe in transubstantiation.
2) Transubstantiation means, literally, “change of substance.”
3) In this instance the substance change involves bread and wine being transformed into the Body and Blood of Jesus Christ.
4) Therefore, Catholics believe that bread and wine are no longer present; only the Body and Blood of Christ.
5) And the adoration of the host and eucharistic worship takes place after the consecration and change of substance in the Mass.
6) Nevertheless, we will accuse Catholics of worshiping bread and wine instead of Jesus Christ, which is gross idolatry, and no part of legitimate Christianity.
Obviously, #6 doesn’t follow, based on the premises of #2-#5. So how is it we get accused of idolatry, when the very word that describes the practice being so critiqued proves that it is not taking place at all?
If anything, Lutheranism would be more open to this accusation, on the grounds that they might conceivably confuse the elements with Jesus, since in their view, Jesus is truly present, but alongside (rather than in place of) the bread and wine (I would not make the charge myself, I hasten to add, but I am making an observation based on anti-Catholic premises).
But that is not true in our case, by the fundamental definition of a complete change taking place, as we believe. So again, one can disagree with what Catholics (with virtually unanimous patristic support) believe in faith to be occurring, but it is ludicrous — utterly illogical and empty-headed — to accuse us of idolatry in the Mass.
Idolatry, by its very nature, flows from the heart: what we ourselves believe), and if in our hearts we believe it is Jesus and not bread and wine, then we are worshiping Him, regardless of whether there was in fact a change or not. We would still be worshiping Jesus in any case. Even if it’s still bread and wine (assuming our critics are correct, for a moment), we are worshiping what we believe to be Jesus.
We’re simply not worshiping bread and wine. No Catholic who knows anything has ever done that. It would be ludicrous and gross idolatry. No Catholic teacher in history has ever said that Catholics worship bread and wine. It’s ridiculous to even have to note this (to critics).
Likewise, Protestants who don’t in fact possess the Real Presence (like Lutherans) are still pious if serious about Holy Communion and not engaging in idolatry, even though what is taking place is not what they believe takes place.
In the case of the golden calf, which anti-Catholics often outrageously and ludicrously compare to the Catholic Mass, the ancient Hebrews appear to have literally believed that it was God, without any such miraculous change, and that was plainly idolatry, as the Bible makes clear.
God (and Moses) know idolatry when they see it. In Exodus 32:1, the RSV reads, “make us gods, who shall go before us” (cf. 32:23). Exodus 32:4 informs us:
And he received the gold at their hand, and fashioned it with a graving tool, and made a molten calf; and they said, “These are your gods, O Israel, who brought you up out of the land of Egypt!”
It is, therefore, clear that this is idolatry and otherwise sinful, on two major counts:
1) It represents not even the one God, but “gods,” so that it falls under the absolute prohibition of polytheism which was known to any observant Hebrew (see, e.g., Ps 106:19-23; cf. Hab 2:18).
2) Nowhere are the Jews permitted to build a calf as an “image” of God. This was an outright violation of the injunctions against “molten images” (Ex 34:17; Lev 19:4; Num 33:52; Dt 27:15: all condemn such idols, using the same Hebrew word which appears in Ex 32:4, 8, 17: massekah).
If the above data isn’t sufficient, surely Psalm 106:19-21 nails down the Catholic reply to the charge of idolatry:
They made a calf in Horeb and worshiped a molten image.  They exchanged the glory of God for the image of an ox that eats grass.  They forgot God, their Savior, who had done great things in Egypt,
How could they “forget” the true God, whose glory they “exchanged” for the idolatrous image, while at the same time, in supposedly worship YHVH under the form of the golden calf? That is simply nonsensical. Thus, this is rank idolatry, and in no way, shape, or form analogous to the Catholic Mass.
The devout, orthodox Catholic is certainly not angry, distrustful or “forgetting” God after the consecration, but rather, is worshiping Him. This is a separate issue from whether or not a supernatural change occurs or not. And a Protestant may acknowledge this without compromising their own eucharistic beliefs.