Yeah, it's kind of funny. Like imagine how he would feel if presented with the "opportunity" to work on his own idea with no equity stake. Ideas are great, and it's a wonderful thing to be motived for ideological reasons. But they tend not to be the sole motivator. You usually have a ton of other things mixed in (potential financial independence, feeling like you own something, getting public credit for your own accomplishments instead of being anonymously mixed in with "the team", etc.) The last one is a bit shallow, but whatever, I'm human.
If he wouldn't feel excited about the offer he's giving you, then I can't see how you should either.
We're a place where coders share, stay up-to-date and grow their careers.
We strive for transparency and don't collect excess data.