The whole topic seems pretty petty to me.

There is more than enough work for everyone (if you have a reasonably decent promotion strategy in play). Unless someone's business is hurting clients' maliciously on purpose or otherwise, I find it hard to imagine anyone in the community would really go out of their way to harm someone's reputation in any in-depth manner. Sure, a barb here or there is sort of par for the course, but that's free speech for you... Deal, accept and move on.

Seriously, if a person has that much "free time" for such nonsense, they are likely not going to be successful anyway--and they'll die off of their own accord.