Seen in its full historical context (a viewpoint which is available to us today), Castro’s revolution seems neither as beneficial as its proponents claim, nor as detrimental, as its victims maintain.

Sanders tends to err on the side of ideological simplification. So do Trump and his minions (though who knows for sure if the Trumpers believe what they say).

Still, I don’t interpret Sanders’ recent (or previous) comments on Castro as unqualified praise (which the Trumpers implied or stated directly). Anderson Cooper’s question was a bit slanted (“do you regret saying that….”). If Sanders says he regrets the 1976 statement, then his opponents will use the 1976 statement against him; if Sanders says he didn’t regret the statement because it was more complex than Cooper implies, then Sanders’ opponents will use the 1976 and the 2020 statements against him. Sanders didn’t bring up Castro on his own. To explain in detail his disagreements with Castro by enumerating major instances of the repressiveness of the regime would have lost valuable interview time.

If you want complex stands on complex issues, Sanders is probably not your ideal candidate.