it was 1 bad guy, confined and killing cops... he wasn't coming out alive, no matter what.
the issue with explosives is they have to be able to see every inch of the place before using it. If some kid is hiding from the gun battle under a couch and they blow him up too, it's a huge deal. But if they know he's alone, and they're already justified to deliver lead at 1000 fps... nothing wrong with using an explosive to deliver the same deadly force.
In the old days, wouldn't they just rev up the ol' Dodge Dart Swinger and ram his ass thru the wall at 60 mph?