I'm confused as to what metric you judge the 251 by to deem it an IFV that also leads you to the conclusion that the M2/M3 were not. I mean I can understand the fact that German armored units were using mechanized infantry support before some other nations, and that perhaps that by your arbitrary judgment the 251 was the first to fill this role, but it wasn't like the US didn't have armored units doing the same exact thing with M3s.
It should also be noted that the 251 was no more an IFV in the true sense than something like an ACAV M113. While it had the firepower to support infantry units on the front line along side tanks and other AFVs, it lacked both the durability and tactical flexibility of a true IFV.
>If it brings infantry to the battle and hangs around to support them it's an IFV.
>HMMWVs are IFVs
>Technicals are IFVs
I feel like a big problem here is that you have a fundamental misunderstanding of the neuances of what "IFV" means, and also just aren't very smart.
