That was a totally snark-free text. Trust me, as an occasional practitioner of snark (that I fancy myself I use judiciously), I know it when I see it.
You aren't going to work with him any more, and he's an ex at this point, correct? No concerns about burning bridges?
I'd suggest texting him and saying that unless you hear from him over the weekend, you will assume he's no longer interested in the event and plan accordingly. It sounds like HE has an issue with passive-aggressiveness. You don't have to be his victim.