The advisability of a warning shot is not in discussion here. What is in discussion is its status as a crime in the present context. Context is everything. While it might be a crime to step out your front door on the Fourth of July and fire rounds from your AR-15 willy nilly, it's not a crime if the purpose is reasonably directed at stopping a felon in the act, and reasonable care (considering the circumstances) was taken not to endanger innocent third parties in the process, and this regardless of whether you agree with the advisability of warning shots under any circumstances. Crime and advisability are two separate questions.
I think you have framed the issue correctly there. However, without knowing the law or the facts, it is not possible to know if the shot was legal or not under the circumstances.
"Don't believe everything you see on the Internet" - Abraham Lincoln
