Hanging out at a friends house last night.

[Angrboda]

"Be it so. This burning of widows is your custom; prepare the funeral pile. But my nation has also a custom. When men burn women alive we hang them, and confiscate all their property. My carpenters shall therefore erect gibbets on which to hang all concerned when the widow is consumed. Let us all act according to national customs."
— Charles James Napier

Asking people to pray is their custom. It is not yours. Objecting to being asked to pray is your custom. It is not theirs. Rituals typically function to bind people together and in this case you did not wish to be so bound. I get that you prefer to remain unbound with regard to this ritual, but asking them not to engage in their rituals because you don't want to participate in them and find simply being asked... offensive? seems a bit silly and somewhat worse than the offense you are attempting to prosecute.

Having been asked to say the blessing at dinner one Thanksgiving, I bowed my head and said, "Thank you God for not existing." It did not go over well, but it was quickly forgotten. I'm not saying I shouldn't have said what I did. They had their ritual, and I engaged in mine. Nobody seems to have won in that exchange.