Regarding Medvedchuk arrest
Seen that the guy was repeatedly elected, he clearly has a Ukrainian constituency. In war however, that no longer counts.
Ukraine is being purged of its Russian component, exactly what caused Putin to intervene directly. Only his actions ensure that the purge will be much more comprehensive.
In a healthy democracy, anyone is entitled to stand, and even the most extreme views in any direction can attract support. However, when your country is invaded by your neighbour who razes towns to the ground, and rapes youg girls and murders your citizens in cold blood, then merely arresting one of your own countrymenn who supports the invasion and is the designated head of a puppet government once all the legitimate governamr are put before a firing squad, then arrest is a fairly mild action.