Parents talk too much, and they also talk too little.
An example of talking too little, "Oh, I didn't think I needed to tell you my son is ADD and we take weekends off from his meds. You don't suppose that's why he's having trouble earning his green belt, do you?" *facepalm*
An example of talking too much, "My child is an Indigo Child. They're more creative and intense than other children and the rules don't apply to them. I don't see why she should have to spend time after class straightening up the dojo with all the other children. That's demeaning."
However, I don't think parents these days are any worse than they ever were (or any better!). We've been complaining about kids and their parents since the beginning of recorded history.
I respectfully disagree. My teacher friends in our grade schools tell a different story. They're older, and they've seen the shift towards helicopter parenting and refusing to let teachers discipline children. They tell me stories of not being able to correct children without parents rushing in to "defend" them. ("My child wouldn't have done that!")
It really wasn't like that when I was kid. If we were in trouble we DID NOT tell our parent - because then we'd be in trouble at home too. My parents may not have been involved enough, but I don't remember any parents coming in to talk about how "special" their kids were - unless they had real health or mental problems.