I do not believe anyone should look unfavorably upon those who do not contribute to their Alma Mater.
Speaking for myself, I worked hard before, during and after college to pay tuition. I saw it more or less as a business transaction. Sort of like buying apples at the local supermarket.
While I value the experience and education I received at college, my degree has yet to allow me to be in a situation where I can afford to contribute financially. I do contribute small amounts to other true non-profit organizations, and I volunteer, but contributing to my old school is not high on my priority list.
I have been out of school for 20 years, and continue to receive numerous requests from them each year asking for donations. The amount of what I consider junk mail I receive from my old school is staggering. I have requested to be removed from their mailing list repeatedly, but I continue to get mail from them. I view these letters as a waste of their time, paper, resources and energy. Their inability to cease sending me these letters makes me less and less likely to contribute anything to them in the future.