I think that the OP point about no "Warning of nuclear attack" exemplifies the point SMBComic is making.
It refers to the prior warning seen in Fallout 4 trailer, which conflict with POTUS comment in Fallout 2, that states that the 'Chinese launched first and there was no warning on the East Coast'.
If true, it will significantly limits the option for world building on the East Coast. Otherwise, it allows Beth more freedom to set a parallel story without interfering with the events on the West coast, it change nothing about FO1\FO2(or FO:NV) experience and we can come up with an easy explanation for that single comment. For example Propaganda: "those bastards they hit us first, without a warning!"
Btw that segment from FO4 intro, reminded me of this :
The Citizen's parents were reduced to ash, as they didn't believe the government's bombing raid sirens. The Citizen made their way to the relocation center and is escorted to a Vault by Corporal Armstrong of the 4th Armored Infantry Division. - Interplay, Van Buren