One simple truth: nobody is a category—or likes to be reduced to one.
Not millenials (your point, well made). Not boomers (who you typify no less than you assume they typify you).
All generalizations risk sucking in the particulars, and tend to rankle when taken personally. Keep that in mind when you address a person as a category.
Note: when you say every baby boomer needs to hear something, you are addressing each of them personally.
True: it would be good for some of us to hear 11 Brutal Truths. (BTW, what makes them brutal?) But not all of us. Some of us have known and respected all of those truths for a long time.
A little bit about elders in all times, and not just our own.
Some elders have a lot to offer because they have accumulated wisdom, experience and expertise that can be gained no other way.
Many elders are still doing good work in the world, with people of all ages and in every category one can name—possibly more now than at any other time in history.
Those Truths deserve respect too.
When that respect goes both ways, we can do a lot more together.