> The point is that millennials spend money on frivolous luxuries and then complain that they can't afford anything.

They seem to be spending less (percentage wise) than the previous generation[1]. I can understand why some people would be upset if they were told, "Even though you're spending less than I did on luxuries, you're still spending too much." Particularly when they are told that getting a sandwich for lunch is a luxury they can't afford.

[1] https://www.morganstanley.com/ideas/millennial-boomer-spendi...