Interesting question for all.
I know nothing about the surveyor in question or even who it is or what was allegedly done.
However,
I do know this about the person calling the surveyor names that unless he could prove in a court would be considered slander. I know the terms he's using. I know he's posting the same question, same words, on multiple forums and other places. I know he's taking out paid classified ads for a year in two places to attack the surveyor.
Now, without any more information or knowledge who has the most credibility in your mind at this point?
I can think of two cases of people going on wild rampages against builders with highly vitriolic and inflamed posts on multiple sites and even building websites of their own. I know a lot about both builders and know some part of what was posted is reflective of those builders. However, the way in which they were done quickly destroyed the credibility of the poster and the allegedly harmed boat buyer. In one case it even ended up in court and in spite of some good evidence the court found the behavior of the buyer so egregious in nature as to rule completely in favor of the builder.
There are ways of criticizing and exposing without going too far. Words like "fraudulent" are immediately slanderous against an individual unless you can prove fraud, as in the crime of fraud. Doing a horrible job. Charging too much. Failing to discover something. None of those things are fraud. Calling someone a crook if they've not committed a crime is dangerous.
State facts clearly and best without names. State what are your opinions as well, but make it clear those are opinions and don't use words like thief, stole from me, crook, fraud, criminal. If any of those things happened call the police or engage an attorney and go to court. There are fraudulent businessmen but social media and forums are not the place to deal with them. Opinions are protected but only to the extent they are based on reasonable information.
Anger is not well used for vendettas. Best used to take time, compose oneself, then figure out the best approach. I would also suggest before using any names in truly forceful accusations that can't be supported by facts, one is very careful and even gets an attorney to review in advance. Also, even if you're 100% right in your mind, be thoughtful of how deep your pockets are and how much legal expense you can afford. I can point out a struggling photographer who lost her business but gained wealth at the expense of a blogger. I can point out a horrible restaurant that should have gone out of business and likely would have where the owners got wealthy because of a coach and his wife making a public statement they couldn't substantiate.
I've been around long enough to have been wronged, to have chosen to never do business again with some, but never to have devoted the level of energy I see some do to trying to somehow seek revenge.
Revenge, when coated with anger, can make one go blind to their own welfare.