I am neither a HBCU student nor an alumni, but I'll like to offer my perspective
I grew up in St. Louis in a Black neighborhood and attended a Black high school--Sumner. Thus I knew what it was like to be around people who looked like me, etc. My parents felt that I should attend a non-HBCU to learn how to deal with White folx.
I went to SIUC.
My daughter was born and raised here in Minnesota. I felt it very important that she attend a HBCU to counter her experiences here. She went to Howard and it was the best decision.
Although she had excelled in the schools here, there was always that question of whether it was because the White teachers had lower expectations. At Howard (and the same can be said of all the HBCUs) she wasn't that token high achieving Black girl but one of nothing but high achieving Black students. Excelling there took on a whole new meaning especially when the professors expected you to excell and didn't coddle you or let you get away with less then your abilities. At the same time they instilled in her a wonderful sense of her Blackness and the richness or our history and culture.