There is a verse in Qur'an saying something like: "leave the 'fools' or the ones who mock in a debate/conversation until the topic is changed." The gist is that we should not force our opinions on others nor waste our time debating nor exchanging insults. Can't remember what surah that verse in, please tell me. This verse in question along with verse 2:256 & 3:20 would help me pointing out that in Islam there is no compulsion in religion. Thank you. May Allah increase us in knowledge.
The ayah you're referring to is probably An-Nisa' 140:
وقد نزل عليكم في الكتاب أن إذا سمعتم آيات الله يكفر بها ويستهزأ بها فلا تقعدوا معهم حتى يخوضوا في حديث غيره إنكم إذا مثلهم إن الله جامع المنافقين والكافرين في جهنم جميعا
And it has already come down to you in the Book that when you hear the verses of Allah, they are denied and ridiculed; so do not sit with them until they enter into another conversation. Indeed, you would then be like them. Indeed Allah will gather the hypocrites and disbelievers in Hell all together
Here is another similar ayah:
[6:68] When you encounter those who gossip about Our revelations, turn away from them, until they engage in another topic. But should Satan make you forget, do not sit after the recollection with the wicked people.
The righteous are in no way accountable for them; it is only a reminder, that they may be careful.
So leave alone those who take their religion for play and pastime, and whom the worldly life has deceived. But remind with it, lest a soul becomes damned on account of what it has earned. It has no helper or intercessor besides God. Even if it offers every equivalent, none will be accepted from it. These are the ones who are delivered to perdition by their actions. They will have a drink of scalding water, and a painful punishment, because they used to disbelieve.