Should I change it to "can be a foreign concept?"
While "grown adults" may be familiar with the difference, 18-22 year olds, many of whom might come from modest backgrounds where ANY sort of philanthropy/donations were rare, may not be. Many development efforts these days are geared towards the "rising generation;" it's the idea that if you get a young person to donate when they're young and have less money, they'll continue to donate.
Also, donations aren't the ONLY way to be an engaged alumnus; I'm not sure where I said that since I mentioned my history of donating AND volunteering.
When I didn't give much money at all, I still volunteered like no one's business. Now that I have less time to give but more $$$, it's easier for me to write a check.