whos deleting all these questions?

That would be the members of this community. It's their reports that got the questions removed from the site.

Every user here has the ability to report any post (question/answer/comment). Posts are removed when enough users report them as violations. You can post again here and ask "Was this question a violation" and include the exact text of the question, including any updates, URLs, or images associated with it, and the users here will tell you if it appears to be a violation or not. If not, you have 7 days to appeal to have it reinstated. 

there is no "who"

the machine deletes whatever is reported by enough users

assuming they haven't reported 20 post of the same author that week already

Its not possible to know who Reported it Unfortunately Reporting is Anonymous

The only thing you can do is If you Believe you did not Violate any Rules you can try Sending in a Appeal for your Question 

To Appeal go here

https://io.help.yahoo.com/contact/index?page=conta...

Select Contact a Yahoo Specialist then Appeals then Follow the Instructions from there