Your Gods all belong to me.
Believers complain about others "insulting their God" or doing things "their God" doesn't like. If you know that gods are fictional creations then it's possible to miss the other implication in the phrasing. That a particular God belongs to them.
Surely there can only be one God. The creator of everything including atheists. So God/Jehovah/Allah is my God too. My relationship with my God and how I speak about him is my business. If I want his picture on my wall that is my choice too. People have ideas about what God wants them to do, but my ideas are just as valid unless they can prove that theirs come from something other than intuition.
So if I say that Jehovah, Allah or Siva want me to eat fish on a Wednesday, stand on one leg during Songs Of Praise or go to work dressed as an egg then that is just as important and real as the claim that Allah wants believers to pray five times a day.
There is one way for the complaint to be reasonable and that is if they mean "The God my church made up". Not so much blasphemy then as an infringement of their intellectual property. If any Christian, Muslim or other believer wants to claim a God on those grounds and stipulate that he doesn't exist then I'm willing to concede that they have prior rights to him/her/it.
Until then I'm keeping my poster of the Virgin Mary serving pork scratchings to Allah, Jesus and Jehovah while they watch the world cup and use their magical powers to help their favourite players cheat.