Scroll down to "The Work Ahead."
https://obamawhitehouse.archives.gov/blog/2014/07/21/preside... https://obamawhitehouse.archives.gov/blog/2015/04/08/petitio... https://obamawhitehouse.archives.gov/the-press-office/memora... https://obamawhitehouse.archives.gov/the-press-office/2015/1...
Obama could only enact laws that congress passed, and they pretty much only did that his first two years until Congress became a logjam and stopped doing anything. So Obama was left with the only tools he had, which were to enforce those laws he wanted to, and not the one he did not. And he did a lot of that, as pointed out.
Edit: His Justice Department also sued states over voter suppression and investigated racist police departments.
I understand some broad facets of the law and I don't believe it was a disaster, and furthermore I suspect you don't understand it either - by what basis are you calling it a 'disaster'?