Since the beginning of wod, I have only ever seen one person kicked for truly just being undergeared. Every other time was due to one of a few things: lack of co-operation, consistent afking/being dc'd, refusing to fix poor play, or terrible attitude. The thing about threads like this is you only have his side. He says he was kicked purely because he wasn't as geared when realistically there could be plenty of reasons that warranted a kick.
TL;DR- Don't assume things just from biased information.