For his behavior, it would be more understandable if his name was Flowey.Sorry
Although the ban reason he put there is quite stupid itself, you crossed the line for him by saying he's a bad host.
By saying that, you can easily get banned/kicked/muted from quite a bit of servers.
It is quite unreasonable though to ban someone for such a minor offense.
Overall, I'd say that you both had your own faults.