I would simply say it's a matter of choice.
To me, proprietary-os "sucks" , but it is choice of billions of people.
Similarly, I like zsh over fish, so I simply use it, (thogh it's a bit slower than fish and bash)
It's just a matter of choice.
Delete his shell history.
Nothing.
No I will ssh into his computer and sudo rm -rf.
Throw a tantrum!
Write an angry tweet explaining how assembly language is the only language that should be used and that a GUI is only for people who are to stupid to speak fluent binary.
The right tool for the work that needs to be done.
Some like bosh some like milwaukee and that one crazy dude across the street build his own drill which is a weapon to surpass metal gear!
I like to hear different opinions and to try out new stuff.
But in the end I use the tool that gets the job done the best way possible for me.
Cheers 
Exactly, lol.
How am I supposed to use TTY then? (Sad enby noises 
)
I stopped using fish after experiencing how long the startup time is...it makes any terminal slow. But that's my opinion, yours may differ.
In terminal simply type:
bash
Problem solved. 
or even better
sh
Stop using fish ... it is not that good anyways 
It's better than zsh
Some like blondes others brunettes, I don't care, I've learned to eat what's on the table.
And, because everything has already been said here and in all the other forums in the world, I'll close here.