The site displays an interesting view of the pages) should I get rid of it?

Question

Search Engine Optimization

a) There are "garbage"" pages (see figure below)

Combines such pages "register="
b) Discussed applicants are closed by a rule in robots (see figure below)

In this case, questions arise:
1) Where do these pages come from?
2) If they closed in robots, how then are they indexed?
3) And how to deal with them?
4) How to prevent their appearance?
Very grateful for the answers

Answer 1

By points
1) From the registration/authorization component - parameters called during registration/authorization
2) They are closed later than scanned and can be in the index for years. This does not mean that they have weight
3) Why, if you told the robots not to take them into account? But if you strongly need a robots meta tag with noindex on such pages or global canonical for all such pages on one main
4) Completely - Remove authorization. Not quite - change authorization