A nutritional diet leads to a healthy and vigorous body & mind. It is one's own responsibility to maintain a good eating regimen so as to sustain the demands of the body and prolong its healthy state. There is a lot of conscious effort that goes into doing this; you avoid temptations and sacrifice your favourite meals in place of nutritional snacks. All this is done with long term goals in mind.
Shouldn't this same ideology apply to our mindsets?
I believe it's one's own responsibility to ensure a healthy mind full of amazing and healthy thoughts. Like I mentioned before, your mind is an input/output machine.
Once at a certain age, you don't depend on your elders to continue feeding you. So why would still depend on others to educate you and tell you what to think. If you care about your mind and its potential, then it's advisable that you start taking responsibility for it.
Much like a strict diet with short term pains and long term gains, the same applies to feeding your mind with the proper information. It's definitely not easy, but once you build momentum, the habit becomes self sustaining.