I don't think we can say for an absolute, 100% certainty that TNA lets talent get away with more stuff than the WWE. We go by what we read on the net and sometimes, there's no validity to any of it.
Going by what we've seen thus far, however, I'd probably have to say yes. According to various reports, allegedly, TNA turned a blind eye to Hardy's drug issues so long as he was able to go out there and do his job. The WWE was certainly guilty of this in years past as was WCW and any number of wrestling companies during the territory days. What happened at Victory Road back in 2011 is probably the strongest evidence to support a theory that TNA is lax when it comes to enforcing a drug policy. Hardy came out to wrestle a main event match with him as the TNA World Heavyweight Champion and was so intoxicated that he simply couldn't perform in the match. If Hardy had been in WWE and he came to a match high as a kite or so drunk he could barely walk straight, he'd probably be terminated before the night was over. The WWE certainly wouldn't have made Jeff Hardy their World Champion and/or the face of the company while he had drug felony charges hanging over his head either.
Allegedly, issues regarding painkillers is what lead to WWE & Angle parting ways. Or, at least, that was part of it. I respect the crap out of Angle and what he's done for wrestling but, again based on what I've read so I'm not trying to come off as if I know the guy, he sounds like that he has a pretty big ego and all but demands that it be stroked on a regular basis. If he doesn't get that, he raises hell. Remember the stuff about Jarrett dating Angle's ex wife Karen a few years back? Allegedly, Angle was so infuriated that he threatened to quit if Jarrett wasn't released from TNA. The problem is that Jeff Jarrett still owns about 28% of TNA so they can't just let him go, they don't have the legal right or ability to. However, Jarrett was pretty much exiled from TNA television for more than 6 months and had nothing to do with it. Dixie Carter will give Kurt Angle anything he wants and Vince will as well, to some degree, but the days of him being held hostage by talent refusing to wrestle at the last minute until demands were met, like the Ultimate Warrior is said to have done at times, are over with.
At the same time, to some degree, it might not be as much about negligence as it is leverage. TNA is still a growing company and even though the huge names haven't really contributed in terms of house show attendance, ppv buys or television ratings; they still feel that they need already made stars to generally carry things overall. Angle & Hardy are guys that don't need TNA financially. They were made guys well before they ever left WWE and that gives a wrestler an advantage. Why do you think Randy Orton is still one of the biggest stars in the company right now instead of jobbing out on Superstars? He's valuable and he's set financially. Comparatively speaking in TNA, so are Hardy and Angle, at least they are in the minds of the TNA brass, and maybe they feel that they can't do without them at this time.
Vince is someone that does rule WWE, for the most part, with an iron fist. That can be a good thing and a bad thing. Dixie is someone that's more approachable and generally gives off a friendly vibe. That can also be a good thing or a bad thing. Vince is something of a control freak that thinks he has to micromanage every detail of every aspect of the company. Or, at least he used to be as he has lightened up over the years. For instance, he allows Triple H to be completely in charge of what happens at NXT and the WWE Developemental system as a whole. Dixie is someone I've heard described by fans and insiders as a true mark, which means some have taken advantage of her or have tried to. Remember all the lackeys that Hogan brought in back in 2010? Dixie brought those guys in mostly on Hogan's word because she trusted Hogan as she's someone that doesn't really have the knowledge to judge talent herself. Remember the alleged conditions in which Paul Heyman would have to have before he'd come to work for TNA? An obscene amount of money and complete, 100% creative control of the TNA product. Heyman wouldn't have even thought of asking a deal like that of Vince as he'd get laughed out of his office.
As far as negative issues go, I do think you can get away with more in TNA than in WWE. At the same time, I think talent can get away with more positive aspects in TNA than WWE due to Vince's controlling personality.