It's generally supposed to be loose to line the petcock up with tank correctly but if seized up or somebody did something silly like loctite or glue........on second thought, sometimes the inner o-ring seal can hang low and get wadded up in the threads to seize up too.
Got it! Thanks @amc49
The bolt was extremely seized and I didn't realize it's reverse threaded at the petcock (Rookie mistake), I introduced it to a blowtorch and it decided to loosen up!