I would have to know why they did it, but if the party they banned is supporting Russian control of Ukraine while Russia is invading Ukraine and a war is actively going on, then yes obviously you have to fight not only the invaders but also anyone who helps them. Whether or not this is the real reason for the ban I don't know, because I don't know the details.

Those on here complaining about democracy, NATO, etc., should remember that Ukraine comes first above all else. When Ukraine itself is at stake, democracy or no democracy doesn't matter anymore.