Question about foul speech of an Indian Politician…

In india, a hindu politician has uttered foul speech regarding the Prophet sallalahu alayhi wasallam. Protesting against this, the ahlul bid’ah like hanafis deobandis they are organising a stage program. The local Jameeyat Ahlil Hadeeth people are even participating in it. My question are

Firstly, is it permissible to organise peaceful demonstration like lectures on stage in grounds as a protest against the remarks and putting forward the example of the Prophet sallalahu alayhi wasallam?

Secondly, Is it permissible to attend the conferences of ahlul bid’ah in this matter as a support to the protest by Muslims in india?

Jazakallaahu khayran. “