I'm going to be brutally honest here. I think it depends on what life opportunities are open to you.
Yeah its not good that deprived areas are 'targeted' as such but on the other hand they do give people who might not have too many other options a chance that a lot of other organisations don't offer. I don't see too many employers rushing out to give opportunities to people who might otherwise be considered 'uneducated' or 'a problem' sadly.
Joining the army is a big risk, but its also an opportunity for people to have a different form of education and be treated in a different way and find a role and place within society.
If your alternative is sitting on the dole, with little chance of getting a job and maybe you are the type of individual who perhaps would be inclined to turn to criminal activities as a result... well is that as much of a risk?
The idea that its being sold a lie... not sure I totally agree with that. I think the Army is glorified but only to a degree, but I also think a lot of teenagers who join would be aware of that and weigh it up against their total lack of other opportunities.
I certainly don't think its a black and white issue. As much as I don't like war, I am also aware that having an army is necessary and not all army roles are front line and many campaigns are peace keeping in nature rather than aggressive. I look to Libya and Bosnia as more positive examples than Iraq and Afghanistan.
If the army was all bad, why do university educated people in their mid to late twenties join? The death rate amongst the lower officer levels, I believe is sometimes higher than some of the more junior ranks as the modern British army relies on these men to lead a lot more by example than it did in the past (I could be wrong on this so if I am, please will someone correct me)