They aren't committed to the game. It isn't about banning them, it is about having a healthy cricketing ecosystem.
Zimbabwe imposed a self inflicted ban from Test cricket when they weren't able to compete. My grouse against Bangladesh being that they weren't anywhere near the top sides despite having the best of facilities. Of late, they've picked up their game and can be viewed as serious challengers in any bilateral.
With the WI, I don't see any reason why they need to continue playing as a unit. There's no national patriotism due to which people play for them. Their main players prefer to represent franchisees and aren't serious about the game at all. If this is what their future holds for them, they might be better off in dissolving the 'West Indies' altogether than be a joke of the cricketing world for ever. This is evident from their fortunes since CWC 2015- where they lost to the Irish. For a nation with a cricketing history as rich as that of WI, they have neglected the game for ages.
They have been a part of 2 World Cup Qualifiers. That's really a dark mark for a full member. They haven't been great/competitive in either format of the game since 2015.(Say 2916, as they won the T20 then) Sorry to say, but this is the reason why I'd want them to split into individual Caribbean islands and ty and play/qualify.
Cricket today requires competitive nations, not someone who just fills up the numbers. The number of posts on Twitter that have come out in support of the WI is a bit ridiculous. The writing was on the walls since ages.
Unpopular opinion here- this exit will have no bearing whatsoever on their fortunes in the coming years.