Hannia, while the people certainly could have been nicer to you instead of outright kicking you out of duties, I have to say that if you're really getting grey numbers you're not contributting as much as you should.

Grey numbers means you're on the bottom 25% in terms of DPS out of all the people who played your job in that content, so it can be questioned that there's a lot of room for improvement in your play. On high-end duties such as ex trials people will EXPECT you to be able to do decent numbers, because DPS is a form of contribution that all roles can offer. Even if you hide your logs, as long as you don't work on improving, people will keep complaining about your DPS. You don't even need to go full on Sword Oath for starters, just try to minimize how many times you use your aggro combo and stick to your dps rotation and you will already be able to do acceptable damage.

That said I have no idea why people are kicking you out of dungeons or even worse, hunts. I never kick people for performance reasons on casual content unless they flat out play badly/lazily on purpose.