You talk as though it doesn't already get (false, incidentally) accusations of being a wargame already.
Not necessarily referring to any form of D&D, actually. There are a group of people who believe that a game excluding interaction rules means that no interaction takes place, or that the game discourages it, while there is also a group of people who believe that such rules inhibit play.
The same argument comes up for things like hobby and profession skills, as to whether it's important to have them or not to have them.
Just as some who oppose silo-ing claim that being forced to have combat skills makes the game about combat, while a reverse claim might go something like:
Any system which allows a character to sacrifice non-combat ability for improved survival is one that discourages social and other non-combat interactions. Mathematically speaking, the character most likely to survive is one designed for combat and any particular non-combat facet is often handled by some other character, which also encourages one dimensional characters and splintering of play experience by expertise.
Of course, there are flaws in both methods. What _really_ makes people care is the type of game the DM (or adventure writer) sets up - the more that non-combat situations are thrust upon the players, the more they'll respond.
In a non-silo-ed game, people are more likely to be left in the cold in any particular scene, but good character design will often compensate. In some cases, it may even be possible to compensate so much that you can do _anything_ depending on how the game works.
If the game is silo-ed to begin with, then it's just a safer assumption that everyone will be able to participate. For some people, that's not a benefit - for example, some people actually want to punish those who care most about combat by making them horrible at non-combat situations. I'm not entirely sure why, but it's true nonetheless. The biggest potential harm is to realism and freedom of customization for your character, but in truth very few people are so one-dimensional that they can only do one thing, so making people diversify is often a good idea.
Especially in a leveled game, where you're already making different assumptions from point buy, so silo-ing works well.
P.S. 4E is not a very well silo-ed game. Even if it is more so than previous editions.