what about solana makes it easier to create vanity suffixes for addresses?

Key grinding is literally built into the low-level functionality of the chain. 

I run a rust script nonstop to grind keys that end in jest for example. But even a simple typescript script could accomplish the task (albeit about 100x slower).

Does this mean other people can launch fake jest suffix addresses?

of course. same is true with ...pump, ...bonk, etc. the suffix isn't tied to any form of authentication. but the deployer can't be spoofed.

we keep a db of our jests as well so we can always cross-reference any suspect addresses.