The Image of bread and wine is a common symbol or image for christians across the globe to represent the body and blood of Christ, same as how the fish symbol at one point was a common sign of christianity, and how some christian demoninations only use a cross, or methodists use a cross and a fire flame i guess representing the Holy Spirit. And then Catholics have the Crucifix to signify they are Catholic.
So the image and symbolism is just that across the board.
Where things differ in regards to bread and wine becoming the Authentic Body and Blood of Christ is very limited to the Catholic Church, and what the Catholic Church will consider to be on good terms with the Church and allow Catholics to recieve communion in those institutions when a Catholic Church is not near by.
So while other religious institutions that have broken off from the Catholic Church and are no longer in good standing with the Church, like Protestants… Their bread and wine is just that, nothing more than symbolism which is bread and wine.
So just because one goes out , gets a theology degree, puts on religious garments, buys some property and gets established as some kind of religious institution, and just because they have some form of communion, doesn’t make it real.
Like medicine, if you will, or scientific studies, where one group is given real medication to test the pros n cons of said medication, and the other is given a placebo. The ones given the placebo dont know they have been given one, and may or may not exhibit haven been given the real thing, while the group with the real medication, will display real pro or con symptoms and etc etc.