I'm struck by the sheer quantity of posts on this topic. It's really not that big a deal, it's just how theists tend to "think" about adversity and suffering. It's disordered thinking. Leave them to it, you're not going to change it. They think they're being kind and helpful. They don't know better. Don't spend the rest of your life abreacting to the foolishness of others.

"Whatever keeps you off the street."

Eh. I can talk Jesus and even pray for people if that's what they want. I don't have any problem talking to an invisible person in the ether. I talk to myself most of the time anyway. If it makes people feel better to pray or be prayed for, I'm happy to play along.

You pray for me, I'll write a letter to Santa for you.

"Well, that's fucking rude."

I'm not that concerned about profundity. It's usually lost on them anyway.

If they're nice? "Thanks".
If they're being nasty? "Thanks, but as with many solo nighttime activities, it's only yourself you'll be pleasing."

"Thank you. I know you mean well and you aren't just saying that to offend my beliefs, so thanks for the love. We all need that and it is appreciated."

It works well because if they are trying to offend your beliefs they look like a butt hole, but if they are not you don't come off as being a jerk to someone who is just trying to be kind.

Or I just say thanks and let it be. The tone of my thanks would reflect the sentiment of the statement.

I usually try to be nice but I have answered obnoxious Christians by, "Thanks; I already have a Jewish and a Muslim friend who pray for me, so with your prayer I am now fully covered." It might be even more effective to add that a Voodoo priest also casts spells on my behalf.

I would just say... "Okay"
I won't thank, because there is literally nothing being done for me, and would not say anything bad as the person has good intention.