If the real reason behind hiring cadets direct from flying schools is cost cutting, then why don't the hiring agencies say so.
Probably because openly claiming that any business now is all about (short-term) profit is still not universally en vogue.
Granted, there are situations when the comparatively quick and effortless judgment and action of an experienced person may lead to a mistake which a newbie who proceeds slowly and meticulously would have avoided, but that has little to nothing to do with bad or careless habits. Supersized egos and a reluctance to be corrected by a less experienced crew member may be a burden, too, but are not necessarily related to experience. Also, the research I know has shown that time-on-type is more important than overall flying experience, but that, too, is a completely different subject than "bad habits".
However, to be fair, I do not think that management's preference for less experienced (and younger?) pilots is just about money. They will also swallow more pinstripe-suit BS than seasoned professionals.