The vote by the parliament did follow formal procedures: not those of an impeachment, because the president was not impeached, but those of snap elections, as the parliament chose to replace the government through elections. In terms of legitimacy, general elections trump over everything else. A coup is commonly defined as an illegitimate seizure of power by a small group. General elections are the polar opposite, the furthest thing from a coup.

Regarding the Crimean referendum, I do have objections: international law considers referendums held under foreign military occupation illegitimate, and rightfully so. Had Hitler staged a referendum in occupied Paris after the invasion, would that have meant that the French willingly joined the Third Reich?

The Crimean referendum is nothing new. In the 1940s, the USSR also staged a series of votes to legitimize their invasions of European nations. At this point, I would consider anyone expecting me to take these referendums seriously as either severely underinformed or simply maliciously trolling.