I obviously don't know you enough to know if you are actually arrogant (in my opinion), but I personally see a pattern with people who call me arrogant (happens often, and as for you, often in case where I can help, and am ready to help).
I found out that it's generally coming from people who WANT to find me arrogant, to raise their own self-esteem, although they don't really have an example to give on why/how I would be arrogant.
These people generally do quite well with actually arrogant people (ie. people looking down at them, not listening to them, generally not giving them any interest). They don't like them but just let them be. But they are annoyed at my knowledge and self confidence precisely because I am open to share it . It's an issue I have always had, but dealing with a specific person for a few years, made me understand it's about not liking to find in helpful people some quality that they don't personally have. It seems to upset them more than when these qualities are found in people they have no respect for.
No idea how universal it is, but that's what I understood from my experiences.