No I don't agree that people should avoid looking at the tags to not get spoiled, looking at the tags help you understand what kind of manga it is and also to avoid certain stuff you might not like, I instantly avoid "cheating" and "futa" or "watersports". Also tags don't really tell you the whole story except for "cheating" and "wishful thinking", those two you can immediately put two and two together and voila, you just figured out the whole story, spoiled.
I think it's nice that they avoid using those tags when they can spoil a story's plot really easily, they usually only do it for the first couple days too and then end up tagging them along the way. So this is why I dissagree with that mentality, because in the end they get tagged anyways lol.