I tried it and left it many years ago. It was obvious, not having downvotes made it easy to agree, but more effort to disagree with posts and comments. In order to disagree, you have to write a comment, which also could be buried if many people responded. To agree you just press a button, which also conveniently shows a counter. The author of a Twitter post may never see the 2000 disagreeing replies behind the 100 first agreeing by his followers. He looks at the likes and sees 500 “wow nice”, but he can’t see thousands of people who didn’t have time to reply and didn’t have a downvote button.