1. Sure, you can call what the FDIC did with respect to SVB an exception, but it wasn't without precedent, and there was a defined process for dealing with situations that could lead to "systemic disruption". That's very different from some sort of bailout for Synapse, where the FDIC never had a relationship with them in the first place. Furthermore, while it's fine to argue about moral hazard with the SVB bailout, no taxpayer funds were used here, and my understanding is that nearly all (if not all) of the money to make depositors whole came from a forced sale of SVB assets. Any balance came from FDIC insurance premiums from other banks.
2. "But I don’t think Synapse customers were SV startups owned by VCs" - that part is just wrong. Lots of Synapse's customers, i.e. the companies who purchased access to Synapse's APIs, most definitely were startups with big VC investors.