I believe Thales has just been going through a rough phase lately (e.g. his mom was just recently discharged from the hospital after 50 days intubated with Covid) and not a permanent decline in his performance. It also doesn’t help that he was in his first Olympics with massive shoes to fill and with the team that was favorite for gold.
Also Renan and the team have a massive soft spot for him, as they say, he’s part of the “clique” unlike Maique. I doubt Twitter comments are going to influence Renan’s decision all that much. Nobody cares or should care about the opinions of fake Twitter fans who started watching volleyball last week because of the Olympics, much less an experienced coach who has worked for years with his team and knows how his players usually perform.