Dont insult the idols of disbelievers

And insult not those whom they (disbelievers) worship besides Allâh, lest they insult Allâh wrongfully without knowledge. Thus We have made fair¬seeming to each people its own doings; then to their Lord is their return and He shall then inform them of all that they used to do.

Al an'aam 108

Comment
The views are probably the biggest emtional asset to a person.and specially those about religion or spirituality etc.It is not easy to change one's view.Islam teaches us to preach with wisdom rather than emotions.therefore it is prohibited to insult their idols (specially in front of them).Rather keep denying their views in a civilized manner and clearly.