As for the legitimacy of the ousted a President, well it was their Parliament that voted him out, not the protestors, and they represent the electorate.
And there legal right to vote him out has been shown to completely legal according to what Ukranian law exactly ?
Has the law been tested in court ?
Does it correspond to the Ukranian Constitution ?
Nobody has checked a single piece of this only MOB rule is ok because the West likes the result.