It's not because of what it reminds us of in the death of Christ. ("God forbid that I should glory save in in the cross of Christ.") The problem is, visible objects are sometimes used in lieu of saving faith.
So, objecting to the use of crosses is based on a serious concern about idolatry. This is not really what the article is talking about.
(Protestants do object to the RC mass, too--and the reasons are related to what you mentioned--but more important, we object on the specific grounds that the sacrifice of the mass violates the Book of Hebrews, especially Hebrews 10.)
Thanks. I wasn't aware of that. Makes sense. I just assumed the only people with this view were liberals whose ultimate goal is to have Christianity slowly fade away.