So I think there's layers and nuance to it, and it's not a black and white case of shipping specifically Vtubers is only bad and dangerous.
Well not SPECIFICALLY, shipping singers is bad, shipping actors is bad, shipping people you know from work is bad.
Do not ship real people. That's creepy.
Some people do think shipping fictional people is also creepy, and some other people think your ship is bad because but their ship is good because. Those kinds of people can suck on wood. Ship anime or comic characters you want.
Hell, ship Jack Sparrow and Will Turner if you can separate them from Depp and Bloom. Many people can't or don't want to, but maybe you can.
By this standard, sure, ship "Calliope Mori" and "Kiara Takanashi". Whoever is the person behind the avatar isn't actually a reaper or a respawning chicken. But never bring it up with the actual people who are not just playing, but also "are" their characters, much more than Sean Connery "was" James Bond.
Don't ship real people.
that's what I feel, sorry.