Honestly I don't have time to look through all this. Maybe I'll get time though. At the moment here's what appear to be the facts:
Bryan Malinowski, executive director of Bill and Hillary Clinton National Airport in Little Rock, was fatally wounded in a shootout as ATF agents tried to serve a search warrant at his home.
www.nbcnews.com
There seems to be little doubt that he was knowingly breaking the law. Over 150 guns, 6 linked to crimes, this was quite a serious matter. Maybe he committed other crimes too, as criminals often do. Maybe he knew he was looking at a long prison sentence and didn't want to go. There was that weird business about the postbox where he pretended to be a lawyer and behaved unreasonably as well.
As far as the search warrant, for some reason people keep equating it with them wanting to arrest Malinowski. I doubt it was no knock, and IIRC the law is you have to identify yourself, state your business and wait a reasonable amount of time before forcing entry. It seems Malinowski opened fire between them knocking (and saying 'ATF! SEARCH WARRANT! OPEN UP!') and forcing entry. Possibly he either gave no, or an uncooperative response, then opened fire when they began to force entry, but seeing as he fired on them while they were outside, it would have had to be in the split second after they bashed the door, before entering.
Edit: Unless I suppose he had a reinforced door. The battering ram or that door opening gun thing will open a normal door in a flash.
If he wanted to be sure it really was the ATF he could have looked out of the window, or had one of them hold up ID to the window, or post it through the letterbox, or looked through his Ring, he could have called 911 or the ATF hotline etc. etc. It seems probable that he knew, or at least thought it probable, that it was the ATF.
I think people are just rationalising up fictional justifications for this person's reprehensible behaviour. Still maybe more details or bodycam footage or something will be released, we could only make definitive comments then.