But isn't a first meeting also just looking at a label? You can't possibly get to know someone perfectly on a first encounter. Oh well, maybe INFJs can
It's similar to walking in a crowd, except on a dating site you can see labels that often show important criteria for dating. It makes it a lot easier.
If you were in a crowd, you'd have to approach everyone to find out. On a dating site you already know some important basics and you know the other is also looking to date. So you don't waste your time with people who don't want to.
I believe a large part of dating is already dehumanising. Dating sites just make that part quicker and more efficient. The human part of dating is left intact. After you first met someone, you go on dates and get to know each other. That part is not happening on the dating site and is exactly the same as when you meet someone in real life. And especially for introverts the dating site is much less overwhelming and scary.
People will treat people bad everywhere, not just on dating sites. Nowhere in life you can chitchat in everybody, dating sites aren't any different. The difference is that you have more exposure on dating sites. More guys will see your profile, increasing the chance of encountering dicks and potential interests alike. You can then politely decline those you do not want to invest time in (you don't have to talk to everyone!) and talk to the interesting ones.
I'm always in favour of seeing things like technically really are and not what values society has given to them. I agree that one could see it like a grocery store and I agree that that is dehumanising, but is that bad? It only dehumanises the introduction slightly and in turn makes it easier and more efficient. The largely human part remains intact.