I think it's ignorant to group a large number of people by a specific trait (age, race, sex, etc) and then make a decision based on it. I understand the logic behind it, but I usually prevent myself from personally taking general advice like that.

The general view is that people in their 20's have a lot of disposable income, so, therefore, it's worth putting a couple of grand into something that might blow up and would allow them to retire when they are 30. The same applies for anyone with disposable income, no matter what the age.

Better advice would be "Invest money in bitcoin if you can afford to lose the money and are making a decent sum with little to no financial hardships".