It’s now a felony to send api calls? Give me a break
So, crafting API calls to intentionally bring down a system most definitely can be a criminal offence.
Now if you're objection was to the use of felony as opposed to misdemeanor, then ignore whatever I said above.
The DoJ is unlikely to prosecute a vigilante of scammers, but they have prosecuted others (eg. Aaron Swartz) who were doing a debatably morally upright actions while violating the letter of the law.