SO has long had a policy of closing questions asking for recommendations as "off topic", with the following kind of closure annotation:
Questions asking us to recommend or find a tool, library or favorite off-site resource are off-topic for Stack Overflow as they tend to attract opinionated answers and spam. Instead, describe the problem and what has been done so far to solve it.
Since we now have a graduated site for Software Recommendations, could this response be changed to something more along the lines of:
Questions asking us to recommend or find a tool, library or favorite off-site resource are off-topic for Stack Overflow. Consider submitting this to Software Recommendations.
An alternative is to have the question simply migrated to Software Recommendations. This might not produce high-quality questions because there's no a priori reason to believe the question has been posed well, but SR can probably handle those cases.
See also suggested details for handling transferred questions.
A suggestion that a link to the SR rules be included, to ensure the poster understands the not-implied threat of secondary closure, is an excellent one. Maybe something like this?
Questions asking us to recommend or find a tool, library or favorite off-site resource are off-topic for Stack Overflow. Consider submitting this to Software Recommendations. Be sure to follow their rules to avoid closure there.