Who thinks Millenials are disrespectful?
Those people who demand their undivided attention. It's not the Millenials who are the "Me" generation, that tag line belongs to those who enjoy aggrandizing their own generation as transcendently wonderful and gloriously paradigm shattering.
I believe if those people reflect, they may recall shouting at their parents that they were hypocrites, running off without bothering to let anyone know where they were, and some were doing illegal drugs or lying about major aspects of their life (where they were living, what school they were attending). Further, many assumed everything was meant to be shared: bodies, possessions... rules were anathema, if they got in the way of their personal desires.
And that's the generation that shrieks that Millenials are disrespectful?
Here's the clue: when a child says "you are no longer relevant to my life," then that's because that's what adolescents do. When they are able to be connected with their friends, they do that - just like we talked on the phone for hours after school. Kids these days don't go to each others' houses, they work from sunup to sundown frantically trying to get into college, and they identify with their teams, not believing they can do it all themselves, but that they CAN do well, collaboratively. How, from that, would anyone conclude that they're disrespectful?
Or maybe I should ask: is that the best you can do? Adults have whined that their children don't "respect" them upon reaching adolescence probably since the dawn of time. I think the Millenials are a great generation! They're going through their teen and young adult years looking at a terrifying situation, and they've stayed positive and optimistic.
If you're worried that they don't respect what you've done as stewards of the planet, maybe it's because you don't respect yourself. But get off their collective back.