'Blame' and being the cause of something aren't the same thing, so that's a straw man argument.
Yes, graphs only show averages, but it is an ABSOLUTE FACT that baby boomers are wealthier than other generations, are about to become wealthier pensioners than pensioners have ever been and will be in the future.
You are right that averages hide differences, but the government has pandered to this generation, because they are such a big group and buy votes. What the averages show is that there should not be measures directed at pensioners as a group, but at those within the group who need help, in addition to those who need help in ALL age groups.