Products like 2x2s aren't exactly regulated to the point they have to say what type of plastic they contain.
Even if they say what type of plastic they use, it's just their word.
Imagine you are an unscrupulous merchant trying to sell millions of 2x2s you imported from China. You have heard that the collecting community didn't like PVC, for some silly reason. What would you say about the 2x2s you are trying to sell?