And why do university math courses not allow calculators?

Because, in math courses, they want you do mathematics. All the upper level courses (and some lower ones too) will be proof based, and calculators are not necessary for proofs. I have never taken a maths course (undergrad or graduate) which required a calculator.

I have no experience with colleges, I'll just address your comments regarding university:

Hundreds of students in a class, which means asking questions in lecture is futile. You will have to ask before or after class, or during the break--but 439 other students in MATH 151 have the same idea as you.

What type of questions: I've never had a large class in which students did not ask any questions.

An instructor's main job is research, not teaching, so you get a lot of arrogant and head-in-the-clouds instructors.

Having done a degree in mathematics, I really haven't found this to be the case. Sure, there are a few profs with egos, but you get that in every profession; I've no doubt there are some less than humble cc lecturers.

Some instructors (like John Stockie) get pissed if you ask questions not directly related to the lecture (for instance, material from previous lectures, or explanations about intermediate steps in examples that use material from previous math courses), which means you have to "be on your game" and ask such questions during office hours, or during tutorial. If you easily get lost during lectures it can be torture.

This is what is expected of university students, you should be on your game.

Instructors often jet off to conferences, thesis defences or meetings, alongside their research--they're busy people and don't have much time for office hours (1-2 hours a week).

Lower level courses (i.e. the big ones) will usually have workshops (which are open very regularly) or tutorials + TA office hours; for these there is ample opportunity to seek help. For upper level courses, they won't have workshops but they do usually have TA's assigned with limited office hours and the prof will also have office hours - IMO, at this level, particularly if you are a math major, you really shouldn't need any help.

several challenging math and stats courses are not serviced by the workshop: these include MACM 101 and 316; MATH 242, 252, 254, 310, 314, 320, 322, 340/341; and STAT 285, 330, 350.

The lower level courses you've listed are really not that challenging, and for the 3xx courses, students should be able to complete these courses on their own.