Is not providing lecture notes to math students really beneficial to them?
Writing something down absolutely does help you remember it, as more different aspects of your brain are engaged with the material at once.  See, for example, this CogSci.SE post on the matter.

The cognitive benefits of engaging multiple channels, however, can certainly be outweighed by the detriments of poor lecturing technique.  The problems that you describe having do not actually seem to be about the availability of notes, however, but about the pace of the lecture being too fast and with too little explanation for you to comprehend the material --- writing things down slows you own partly because you have to be thinking about the material and summarizing as you go, rather than just letting it wash over you.

From what you have written, it is not possible for we strangers on the internet to distinguish between two common cases:


The professors you've had were going too fast and not explaining enough to teach effectively.
The pace felt too fast for you because you had inadequate preparation or some other issue.  For example, a dyslexic student would likely need a slower pace.


You may be able to tell which it is by seeing whether most other students are experiencing the same issues as you.  If they are, it is likely a problem with the teaching; if they are not, it is more likely the problem is on your side.