Not quite true about offline, as Blizzard CAN still store ALL online files on their servers and protect them and check their validity and etc. Many games have a single player offline mode AND a completely different multiplayer online mode. Dont know why everyone thinks there HAS to be online only to prevent hacking. Blizzards problem was and still IS 20 year old software. Reminds me of how everyone is brainwashed into believing nuclear power is soooo scary and the devil. In movies they say "it's going critical" and everyone panics! How many people (besides me) know what critical means? Same irrational fear of offline mode. Same people that aren't educated on the subject but spread fear cuz they are ignorant about the subject matter.
When Blizzard updates with the next patch to CASC and uses some proprietary software they may be able to safely allow some offline single player. Who knows if it will happen, but its all about the software and monitoring, and the consoles are running easily hacked 20 year old software. The consoles are also running on non Blizzard servers.
Something you'll notice with games that provide an offline single player and online multiplayer is that the multiplayer is typically easily hacked. It's not that it's not possible to prevent hacking, it's that it's practically impossible. It's not just about authenticating the files, it's about authenticating them while they're being used - which is the primary method of hacking online games. Authenticating a file during a game's boot, for instance, would do absolutely nothing to prevent hacking of that file after authentication. You need constant authentication to have realistic measures of countering hacking.
Any game that doesn't authenticate local files with remote servers in real time will always be capable of being hacked, and online only may not make hacking impossible, but it sure limits it to the point where Blizzard isn't concerned with hacking of their game every week, as would be the case if they allowed an offline mode.
I mean no offense, but you claim to be educated on the matter yet completely ignore the fact the information I've provided that most advanced computer users would be capable of understanding. So maybe instead of being so critical of others' opinions and willing to chalk it up to their lack of understanding you should try to understand their perspective instead? Making the claim as though you're the only educated one here certainly doesn't do you any favors.