What drives a poor reputation for the Rogue class?

[Schwann145]

*am I the only one who considers "passive investigation" to be an oxymoron?

No, you are definitely not alone!

It's a rule in 2024 per the latest Rules Glossary - UA 8 pg. 30.

Fair enough. Pretty awkward that the UA version of the Assassin still grants advantage on Deception checks for disguises, which becomes actually useless instead of just potentially useless like it is now.

This, however, it does not necessarily do. Per the PHB, passive checks are used when the DM might not want to reveal the result of the roll, or they want to represent the result of a task done repeatedly. It's called passive because the player doesn't roll, it doesn't mean that the character is being casual or passive.

This definition is certainly not an exclusive definition for what "passive" means, and it definitely can include meaning the character is "being casual or passive." The only "hard rule" here is that Passive checks are checks done without a dice roll.
Going with the understanding that a Passive check would trigger when you may notice something you aren't necessarily looking for, as compared to an Active check in which you are intentionally searching/investigating/etc.
With such an understanding, you would not have to worry about Passive checks because your disguise is good enough to foil them every time.