What I find is that people consider "saying anything offensive" to be an ad-hominem attack, but completely omit very common forms of ad-hominem attacks such as attacks on supposed ideology or bringing or other views and arguing that their views are contradictory -- or arguing against another viewpoint that they hold -- in an attempt to refute their views.
To use a real example I recently saw: "Russ Feingold said the Patriot Act violates the 4th amendment, voted against it, and says we should repeal it; however, Feingold sponsored the McCain-Feingold act -- parts of which were found to have violated the first amendment -- so his argument against the Patriot Act is invalid because he and other liberals also violate the constitution". This is an example of not only an ad-hominem, but also false equivalence, and to-quoque -- but yet I see these arguments commonly asserted and unchallenged.
For the record I do think the grand-parent comment does not constitute a particularly strong argument to me: there's no proof that Thailand fails to punish paedophiles any more than any other country (keep in mind these kind of crimes are grossly under-reported) and even if that is indeed the case, there's no proof that the same dynamic would mean laws against bitcoin would not be enforced.