Is not providing lecture notes to math students really beneficial to them? I have attended several lectures in analysis, linear algebra and "higher mathematics for computer science students" in two universities in Germany. None of the professors giving these lectures provided lecture notes. Therefore the students had to copy what was written on the blackboard while at the same time trying to understand the material.

The sequence of a lecture was usually:


Professor arrives and gives a short salutation and very brief recapitulation of the last lecture 
Professor immediately continues where we left off and starts writing proofs, lemmas, etc. on the blackboard while explaining the material in parallel. Rarely he stops to clarify something.
When he has filled all three blackboard, he stops to erase one or two of the blackboards while usually continuing to explain what he just wrote down or introducing the next concept.
He continues with the now empty blackboard.
The whole process repeats from step 2 until 1.5 hours have passed.


I found it impossible to copy the blackboard and at the same time understand the material he was trying to teach. During the few breaks (question or blackboard cleaning) that we had I was frantically either trying to understand the proof or was squeezing my eyes trying to decide whether an index is i or j and was making sure to not copy i instead of i+1 or i+j by accident.

Although he did encourage us to ask questions and did answer them when someone did, the general pace was so high, that it hardly gave me some time to catch up.

When asked why there are no lecture notes, all professors said something along the lines of: "You can learn/memorize better if you hear and write the proofs yourself." While I agree that having multiple input channels helps memorizing, in practice, all that most students could do was to barely copy what was written on the blackboard, there was no time to understand. I felt like the students were "demoted" to human copy machines because this is all what most could manage to do.

Considering all this:


Is there really proof that not providing lecture notes and forcing students to frantically copy the blackboard is beneficial for learning math?
OR Are these professor just too lazy to create proper lecture notes?
OR Is my perception warped and I was in the minority and just too stupid to study math?
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.