How many generations back shall we take that particular charge?
All the way back. This is a problem that has been building since FDR instituted the first national transfer payment system in the 1930s. That is why it is unfair to say "the Boomers" are destroying the country by taking SS and Medicare. The Welfare State that was set up by the Dems in the 1930s and that was expanded in EACH generation since is what is destroying the country.
The answer isn't to cut off SS and Medicare but the answer isn't to let Boomers continue on with the program "as is" either.