"Appeasement" is a term often abused, thrown about by commentators who seem to have no idea what it actually means.
..Or even if they sorta do, more or less correctly associating it with what Chamberlain was practicing, they tend to forget that it was in fact a highly successful policy. Hitler nearly conquered the world with it!
Basically everything Hitler did until 1939 was appeasement. He bent over backward to let Stalin better fuck him in the ass so that he could keep oil from the USSR flowing - he gave Stalin free aviation technologies and training, free if half-built battleships, even free territory, all without direct reciprocation merely in order not to piss off the Soviet leader. He caved in on Mussolini's silliest demands, and granted special rights and privileges to all sorts of "neutral" leaders in Europe and the Middle East... All because he could trivially afford to. All his real enemies thought him a ridiculously weak leader, and allowed him to proceed with his plan (or with what would have been his plan, had he had the patience to think of one).
Caving in was a good policy back then, and remains a good one today, because it makes petty players feel empowered and unlikely to actually act against one's interests. Many an old empire appeased its way to long-lasting dominance, and the Federation's "neutral zone", "never-total-victory" policy seems to serve this newer empire pretty well...