But anyway, you can't go shouting down religions and cultures like that, on a megaphone, in a public place, where people of those religions and cultures can hear you, without consequence.
Why not?
Abu Hamza, Abu Qatada, Anjem Choudary, Omar Bakri just to mention a few have done it but don't seem to have been arrested and charged in relation to "suspicion of religious or racial harassment"
Granted these people have all since been arrest/charged on other offences far graver but the point still stands.