Firstly, political posting and troll posting aren't mutually exclusive. Secondly, it appears that there was strong evidence that this poster actually tried to harm the presenter's reputation and career. To that extent, libel charges are fair and it's a good thing he was able to be traced and admonished.

I don't see any details as to what the alleged "troll" said on which you are basing this. The only evidence I see is the this was settled out of fear of being doxed amd nothing indicating the strength of the legal claim of libel.