Me personally; I don't mind ignorance. Simply means they "Don't know". It's ok when they say things like; Too bad s/he didn't get accepted into college or Too bad s/he didn't get into a "Good" college.
I can deal with that. My son however, had a math teacher who knew very well what the air force academy was. He told my son he was disappointed that my son chose the academy. He thought he'd have better opportunities if he went to a "Real" college and not a military school. He thought my son would be limiting himself. We blew it off. A couple years later, I ran into him and other teachers at the high school. They asked how my son was doing. (Most teachers were very excited for my son's decision. He was a school favorite among teachers, principal and football/soccer coaches). I told them he finished his Bachelor's at the air force academy in 4 years; 1 1/2 years later finished his Masters; and another 1 1/2 years later he finished his PhD. So, at 25 years old, he had all 3 degrees; a great paying job; seeing the world; and NO STUDENT DEBT. The teachers were all happy.
The math teacher however had that look on his face. He knew that I remembered the previous conversation and how he thought my son was wasting his talent and abilities. So now, this 35 year old teacher who had just finished his Master's after about 10 years of part time school while working; has to deal with his 25 year old prior student who has a PhD as well as his Masters. (And making a lot more money than him). The look was PRICELESS!!!
FWIW: I normally am not the type that rubs people's noses into anything. We all have our lives, our choices, our talents, skills, etc. that we live our lives around. What's best for one person isn't necessarily best for someone else. But when someone has to take a position beyond their opinion; and try and make it a "Point of fact" without knowing anything of which they speak; I can't help calling them out for being an idiot.