TL;DR: on what basis do some (mostly western) countries condemn the democratically elected Assad?

In my understanding, President Assad was democratically elected. He has won elections 3 times:

  • In 2000 he was the only candidate to run to replace his father
  • In 2007 there was a referendum asking the people whether he should continue serving as president
  • In 2014 there was a difficult to administrate election during the civil war, but he won 88.7% of the vote with 73.42% turnout

Of course it is open to question whether the elections were truly democratic:

Long before the conflict began, many Syrians complained about high unemployment, widespread corruption, a lack of political freedom and state repression under President Bashar al-Assad, who succeeded his father, Hafez, in 2000.