It's called sister because of the fujoshi demographic. You needs to oshi one of the guy, headcanon that he was engaging in anal coitus with another guy.
Not everyone is qualified to be called a sister.
Their headcanon is so strong, they will ignore the fact that kyo was banging enna and mysta was clearly being dicked by mika. It goes against the narrative so it simply didnt happened.
You tend to see these sisters flaming selen, it's because they never give a shit about the female in the company in the first place. "This girl's flipping gets in the way of my husbandos banging eachother, unforgivable"
Who gives a shit about this obvious bait account. Show me the flip girl opinion, mae or whatever her name is. But I guess she haven't woken up. You know the one with 200k tweets in 2 years