They weren't discouraged to do string theory in particular, they were discouraged from getting into the whole "trying to find something better than the standard

They weren't discouraged to do string theory in particular, they were discouraged from getting into the whole "trying to find something better than the standard model." If they anyway went into th hep, they would have slim chances of having any career if they didn't do string theory. They were encouraged to do things like condensed matter physics, not trying to find some alternative to string theory.