You are just a worker. It is a job. It doesn't belong to you.
Avoid getting an ulcer, strokes or aging prematurely. Don't make yourself sick from holding grudges. Settling a vendetta may feel good but the consequences aren't worth it.
If you know what is good for you, let it go. Please! Besides they aren't losing any sleep over it. Why should you?
Business is another word for competition. Everybody is competing to get to the top.
Before you go postal, remember, they weren't really trying to step on YOU, they were just trying to get ahead. That's it.
So, don't take it personal, it's just business.