One of lichess's criteria for a puzzle is that there must be only one winning move (with an exception for checkmates in 1).
This makes it much easier to select for not terrible puzzles with an algorithm, and to have a good UI for puzzle solving, but it filters out many defensive puzzles both because it excludes positions where there are multiple defenses, and it excludes positions where you just manage to not lose without turning the position into a clearly winning one.
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One of lichess's criteria for a puzzle is that there must be only one winning move (with an exception for checkmates in 1).
This makes it much easier to select for not terrible puzzles with an algorithm, and to have a good UI for puzzle solving, but it filters out many defensive puzzles both because it excludes positions where there are multiple defenses, and it excludes positions where you just manage to not lose without turning the position into a clearly winning one.
Wouldn’t a puzzle with only one “non-losing” move be equally easy to find? (Assuming this is based on engine evaluation)
These are called "defense" puzzles and the big chess sites have a category for them.
I don't think that's quite true. I'm pretty sure I've had positions where I can deliver the final mate with multiple pieces and would accept either.
Yes, that's what I mean by an exception for checkmates in 1.