IMAP is a security hole and for policy reasons, they won't do so.
So which part of that is the sysadmins fault (that is if it *is* indeed policy and not an excuse). In a lot of companies willfully disregarding policy is a fireable offence. You apparently think it's reasonable to place someone in such a position, because it's convenient for you to have IMAP.
If this is indeed policy and you're not happy with it, you talk to the implementer of the policy to get the policy changed, you don't blame a co worker for actually adhering to policy.
I need wireless access. Policy states that no wireless device can be set up other than by IT. IT refuses to touch anything on my separate network
Again. If you need this, you go to the person who can actually sign off on you having a wireless network for testing purposes. You don't set up your own and connect it to the company network, because it's convenient and if you do set up yourself, you should have a good talk with HR.
Management approved the purchase and it was all fine. IT then blocked it saying that they supply our standard equipment from Dell and we shouldn't be ordering IT equipment separately.
That's essentially rubbish, but again; this may be policy; if you don't agree with the policy discuss policy changes with the policy makers.
but from my point of view, they do get in the way of us doing our jobs far more than they help
From my point of view, it looks like you're blaming people who follow policy for following policy. If policy is idiotic or if you need an exemption, you go through someone who can change policy or give you the exemption, probably not the persons you're complaining about.