Zechariah 11 can not possibly be about Christ. There is nothing about it can be said about Christ.
Yes there is. It's about a good shepherd over the people, and the rabbinic commentary says that shepherds means kings. Furthermore, the rabbinic commentary says that the flock of slaughter is Israel:
the flock of slaughter: Israel, whose shepherds slew them and devoured them.
Next, the rabbinic commentary says that the good shepherd breaks the staff that thus breaks the power of the Israelite kings.
And I took My [first] staff, [called] Pleasantness and I cut it off to nullify My convenant that I [had] formed with all the peoples. יוָאֶקַּח אֶת מַקְלִי אֶת נֹעַם וָאֶגְדַּע אֹתוֹ לְהָפֵיר אֶת בְּרִיתִי אֲשֶׁר כָּרַתִּי אֶת כָּל הָעַמִּים:
And I took My [first] staff, [called] Pleasantness: I broke the power of the kings of Israel in the days of Jehoahaz the son of Jehu - to the extent that the king of Aram destroyed them and made them like dust to trample (II Kings 13:7) - and in the days of Hoshea the son of Elah, when I delivered them into the hands of Sennacherib and he exiled them (ibid. 17:6).
The Messiah of course would be a prophetic good shepherd or king over Israel. And not only that, but the rabbinic commentary says that it is He who formed the covenant with the nations. And who else but the Messiah is one who is an Israelite king and
who also forms a covenant with the nations and
who also would have the ability and willpower to break the power of Israel's kings if they resist Him, like it says?
Here is a Jewish commentary on Zechariah 11 and you can see it has nothing to do with Christ.
OK. You are linking to Rashi's medieval commentary, and while it can be helpful, the fact is that it is written about 1500 years after Zechariah. Meanwhile, the Jewish Christians from the 1st century AD related Zechariah's prophecies to Christ (notice the reference to 30 pieces of silver in Zechariah and in the gospels). So one cannot simply prove that the Jewish Christians were wrong by pointing to rabbinic commentaries written by their religious opponents. You would really have to cite actual commentaries from 500-300 BC or so in order to show the meaning of the passage.
But in so far as the Christian and rabbinic interpretations agree, like I outlined initially above in this message, they are reliable.