Some right-wingers seem to think so. Anyhow, there is some truth to it, but the attitude of those saying it is often prideful.
In some cases if they're supporting their parents, I would say it's a justified reason. If you're disabled and can't take care of yourself, that's justified. What is not justified is if they're perfectly healthy, full grown ass man capable of getting a job and working, has no desire to work, has kids they won't raise, and sponges off of their parents. That's a major fail. Something went terribly wrong somewhere somehow and it needs to be fixed. I don't think that's morally right.
Speaking of which, I used to be friends with this guy named Charles that did that to his parents for years when he should have been out paving his own way. I think there was some blame on his parents part because they enabled him. He picked up his bad habits somewhere.
When he was barely making it, he moved in with another friend that I know, and sponged off of him. Kevin worked on the road, so he wasn't home all of the time and he was going to be out for over several months. So he told Charles that he could move in and watch over the place for him. He and Charles had been best friends for over 25 years. Since they were little. This turned out be a terrible idea.
What happened? Charles wrecked Kevin's house and when Kevin threw him and his fiancé out, Charles demanded that Kevin owed him this and that, and then demanded money. Kevin didn't owe him money at all. If anything, Charles owed him money for the damages he did to Kevin's house. The guy was a real shithead. Kevin always felt sorry for him and was always giving him a chance. But this was the straw that broke the camel's back because it affected Kevin's children. Charles always seemed to take advantage of Kevin's forgiving nature.
I'm glad I burned my bridge with him. I'm not as tolerant with people. I'm not Kevin, therefor I lack the parts where I'm not as forgiving or nurturing. It was over something else that he did to me. I gave him a chance to come clean and try to rectify his wrong. When I confronted him about it because it was real important to me. I was with this woman that had been seeing him behind my back and he didn't have the balls to do the right thing. He could have not done what he did. When confronted, he shifted the burden of blame on to me because he refuses to take responsibility for his own actions. Cheating, to me, is immoral and it does ruin friendships. What he did next was just as shitty. He spread lies and disinformation to my other circle of friends which I was not going to take credit for. I was done after that. Really done. I've never had anyone shit on me the way he did. It was unacceptable.
I have no problem accepting responsibility for what I do wrong because it allows me to move on. But I will not take responsibility for something when I'm not guilty of it and committed no wrongs. But this guy just really over plays the innocent card to no end. He always finds an excuse to justify it. It's pathetic how he uses his friends and victimizes them. What's worse is that he shifts the burden of blame onto you and tries to twist it around in every way that he can. He'll even dishonestly play the victim. I can't stand people like him.
People like him just suck the life out of people including their parents.