To them, there is no double standard because they're The Good Guys and everyone else is The Bad Guys. Is it a double standard when people cheer when the Avengers win and boo when Thanos wins? No, because you're supposed to boo The Bad Guys. It's good vs evil.
"Haha, seethe more rightoids"
"Noooo, you can't tell me to seethe moar when the tables are turned!"
There's sore losers, and then there's the terminally online.
To them, there is no double standard because they're The Good Guys and everyone else is The Bad Guys. Is it a double standard when people cheer when the Avengers win and boo when Thanos wins? No, because you're supposed to boo The Bad Guys. It's good vs evil.