Yes persecuting is acceptable because they try to spread their religion through propaganda and lies so they must be stopped. Ultra religious people are fanatics and they are a danger to the country and Bahais have shown they will do anything to spread their useless and rubbish ideology.
I agree with you that "Ultra religious people are fanatics" who pour into the streets and shout hateful slogans, write and speak in a derisive manner towards whoever that does not share their narrow views, insult young children's holy figures in school, attack women for not wearing a forced veil, censor newspapers and arrest reporters, vilify legal councils who dare to represent the prisoners of conscience, prevent youth from attending universities, attack people's homes, burn their belongings, arrest people of different beliefs and put them in jail for no reason other than their belief, torture them to force them to recant, execute or assassinate them vigilante style in the streets, and even after their death desecrate their graves....people that do such things are not worthy of the name human, and if they do it in the name of a religion, it is better not to have it at all.
If Baha'is' ideology is "useless and rubbish" as you say, why not let them tell it so that everyone can see for themselves what it is? Why persecute a group whose ideology is useless? Are Muslims not intelligent enough to discover this for themselves that they need to be told? One of the grand ayatollahs should come on TV and have a live televised debate with one of the Baha'is and illuminate people once and for all...