It doesn't matter if Exchange is crap or not. Your personal opinion is pointless if the companies he's applying for use it.
It does, and the reason why is already in my previous post: It's a bad start to learn running email with. The question wasn't about running the software, it was about getting started, about learning to run it.
So learn this email thing properly first, then learn to tame exchange. It's not even much work, and certainly less than having to find out down the road, the hard way, your learned habits are bad ones, unlearning them, and re-learning better habits. It's about getting in the right frame of mind before filling it in with brand-specific experience. Might as well do it properly right away.
Beyond that, experienced admins (ie. a bit more capable than "operator" aka tape monkey) should be able not only to run multiple types and brands of systems, but also advise companies as to what are proper choices, in terms of both functionality to the user ("use") and administration ("maintenance").
Exchange is notorious for offering functionality that doesn't translate to the rest of the world (eg. "un-send"), among other tricks, while being high on maintenance and resource requirements. That is, there are opportunities for better service delivery and lower costs. But you won't be able to offer them if that one program is all you know.
That is another reason not to get hung up on one vendor's offerings, and for that you need interop. So start with software that does interop well, not with software whose vendor has a long, long track record of sabotaging interop in myriads of ways. Once you know how to do it properly, taming the improper stuff also becomes a lot easier.
Nowhere did I say to tell potential employers at the interview that they ought to be doing things differently. That doesn't work, of course. But if the employer is any good as an employer, you'll stick around for a while.
And then you can prove time and again that their decision to hire you was the right one (and get raises, if played right) if you can offer more than "exchange monkey"-type skills; if you can tell them how to get the same or more functionality out of less cost and resources. But to do that you need to do better than stick at "this one application"-level. It's a poor comfort zone to be in.
Might as well lay the groundwork now, even if the payoff is way in the future. We're talking building careers here. That's a multi-decade view.