These people are always going to be there. Just like the unsure, underconfident, second guess everything they know trainers. If you aren’t being affected by their inflated ego then there is no problem. However, since you brought this question up, I’m guessing it is affecting you. Just don’t stroke their ego, slander them, or take ANY abuse from them. I don’t compete with these people (on any level)because they tend to be poor sports, so, I don’t help them either. I only aide those I become stronger from interacting with.
Try to ignore them if you can. Just be your own pleasant self and keep as much distance as you can. You only have to deal with them for a few hours a day (if that much) but they have to live with themselves for the rest of their lives.
One thing I would avoid: don’t talk negatively about them to anybody. If other people solicit your input, do not engage in a bashing in absentiam. I like to follow that rule that if you have nothing positive to say, say nothing at all.
I think “egos” should be checked at the door. We’re just a drop in the bucket when it comes to our small facility. Being confident and sure about our profession, skills and limitations will take us along way. I try to find humor in this type of behavior and stay humble and thankful for the opportunities given to me.