This kind of stuff matters when it's amplified to 100M+ people, and he knows it.
I put some of the blame for the Club Q nightclub shooting that happened a few weeks later (https://www.nbcnews.com/nbc-out/out-politics-and-policy/club...) on this kind of behavior. There's no evidence the shooter saw that tweet in particular, but his homophobia was clearly stoked by this sort of edgelord-ism on social media.