That's bad enough. But to add insult to injury, at least one of those ads bears a Parliamentary logo. It's being done with out money!
Parliamentary communications "must only be used for parliamentary purposes". Readers might want to consider whether organising harassment campaigns against members of the public who submit on legislation is a "parliamentary purpose". And if it turns out that it is "within the rules" - as MP's love to say when caught doing something immoral - whether those rules, or indeed the entire institution, is fit for purpose.
Secondly, among the examples of contempt of parliament are these:
intimidating, preventing, or hindering a witness from giving evidence, or giving evidence in full, to the House or a committee...Rimmer is not (to my knowledge) sending hate-filled messages himself to intimidate, threaten, and disadvantage committee witnesses in retaliation for their evidence - he has an online mob to do that for him. Which he is inciting. And on that front, anything which "has a tendency, directly or indirectly, to produce such a result" qualifies as contempt.assaulting, threatening, or disadvantaging a person on account of evidence given by that person to the House or a committee.
Some MP should lodge a complaint. And if the Privileges Committee finds him guilty, then he should be hoist by his own petard, and suspended for a month.