i don't think this is necessarily a result of an intentional change of approach, it just comes down to circumstance.
when someone is bountied, it's usually done by players. they're not usually around the character in question when it happens and they cant jump to them as a DM would, so there's often no immediate consequence in regards to npcs.
regarding OCR - players cant do it, and DMs are probably too busy to go around manually adjusting the OCR of every single bountied character. i would assume it was possible years and years ago as there were less players, but that's an assumption - could be wrong.
the faction hostile mark often comes from a bountied character trying to enter areas that sometimes have a PC guard presence - e.g. the outskirts. if you're fleeing, it's usually the most you can do as you're often trying to run after the person as well as type. a personal dislike doesn't do anything for other guard pcs, etc, so it's really the only resort. this does bring some perhaps unintended consequences - such as being automatically hostile everywhere and even in different settlements.
that happens because every guard npc belongs to the vallaki garda faction (the ones in barovia, obviously) - even those at krezk outpost and even those at the VoB. you can make the argument that yeah, sometimes the settlements have conflicts but a situation like krofburg harbouring a known, wanted criminal from vallaki is something i've only seen done while a specific plot was occuring and seems the exception to the rule, rather than the norm. bounties posted from one settlement apply everywhere in barovia
i would assume manually adjusting OCR is out of the question. the workarounds would be dev fixes - either making it so faction hostile can be bypassed with influence checks or disguises, or by changing it so each settlement has its own guard faction. i presume both of these would involve some work. effectively you're making changes that make life easier for bountied characters, when really these characters should (in theory) have been given a chance to de-escalate or opt out of the bounty, e.g. by turning themselves in beforehand. so, frankly, i can't imagine they'd be much of a priority. not that i necessarily disagree with implementing either of these changes if somebody was willing to do so