He waited until halfway through his lame duck term to "evolve" his views on marriage equality, only after critical mass has obviously been reached. You're shocked that he didn't also stick his neck out for marijuana legalization, which didn't consistently pass the 50% polling threshold until just last year?

Every time a Republican wins the White House, people instantly put on rose-colored glasses regarding the previous Democrat in office (e.g. Bill Clinton was Jesus during the Bush administration, and it was two decades before people started criticizing his criminal justice record).

No, Obama didn't embrace drug decriminalization. He was too busy bombing Syria and expanding the surveillance state. "Better than the current guy" does not mean a politician was on the right side of everything.