In our reality, we face problems with no clear, unambiguous solution.
The question of whether something is a mitzvah or a sin, or a mitzvah best neglected, or a sin that it is perhaps necessary to commit, does not always have an answer.
The Talmud blames the destruction of the Temple and the exile of Israel on the humility of Zechariah ben Avkulos.
Zechariah wanted to act with complete righteousness and honesty, without deviating in the slightest from truth.
However, had he been less rigid in that situation, had he been prepared to sin a little, the Temple might not have been destroyed.
The final reckoning–What are mitzvot and what are sins?–is not for us to decide, because some factors are beyond reckoning, even for a complete tzaddik.
–Rabbi Adin Steinsaltz
From Opening the Tanya by Rabbi Adin Steinsaltz