I always want as many people as possible to study bitcoin, understand its prospects and do not write nonsense on the forum. But it never seems to end. So perhaps indeed is worth less to pay on this attention.
There are other crypto enthusiasts, adopters, investors and the likes that does not make a lot of sense too. So FUD is not the only matter at hand.
We should carefully asses our engagements with such posts, ignoring them is not the best approach at times. Though i'll have to say, never argue. Deliver your point, drive home the nail and leave. Should they raise a followup question and it deserves a profound answer (and if you have one), responding back will not hurt. This approach leaves some sense to those who are not so knowledgeable about cryptocurrency. Sometimes leaving an issue unattended makes it sound like the truth. Engage with facts and don't attack on a personal level, that's the best approach for me.