Given everything that has happened in the past few weeks and actions by people who claim to be קנאים, the question that needs to be asked is can these people really be called kannoim?
After Shimon and Levi destroy the city of Shechem Yakov is very angry with them and asks them why they exposed their family to danger, they answer, הכזונה יעשה את אחותינו. Yaakov Avinu does not respond at that point but does respond when he gives the shevatim their berachos in this weeks parsha, ויחי. Yaakov says about Shimon and Levi, כלי חמס מכירותיהם, clearly negative and then he says אפיצם ביעקב אחלקם בישראל, that they will be spread around. However, Rashi comments that Yaakov was saying that they will be the מלמדים and סופרים for the Jewish people.
R' Yaakov Kamenetsky asks why should they be the כלי קדש? Yaakov Avinu was not happy with their actions. He answers that to be a כלי קדש you need to be a kannoi. Things have to bother you and you have to act on it.
R' Yaakov then pointed out that Levi fulfilled the beracha while Shimon did not. Levi rallied to Moshe Rabenu's side when he said מי לה' אלי by the עגל, however, Shimon did not. In fact, Shimon used his קנאות for bad in the מעשה of זמרי where the נשיא of Shimon was a kannoi against Moshe Rabenu and acted out his desires. And in fact, who killed Zimri, Pinchas from Shevet levi.
What was the difference between Shimon and Levi? R' Yaakov answers, Torah. Levi learned torah in מצרים and was therefore able to harness his קנאות to torah while Shimon was busy working and therefore his קנאות was not bound by torah and turned out to be a terrible thing.
The Chazon Ish once commented on the Kannoim in Yerushalayim that they were pre-matan torah Jews, meaning that their actions were not guided by torah but by emotion. This is a very bad thing which leads people to do terrible aveiros.
Unfortunately, this is the case of today's kannoim as well. They are pre-matan torah Jews like Shimon. Their קנאות is causing them to violate very serious aveiros for which they cannot do teshuva. They have been מזיק and stole from who knows how many people, an aveira from which there is no כפרה until you return the גזילה\היזק. There is absolutely no heter whatsoever to destroy public property to make a מחאה, it is simply גזילה from the ציבור. In addition, they have created a terrible chillul hashem, again an aveira with no kappara. Why? because their kanaus is not defined by Torah but by their emotions.
When R' Weiss was appointed the Av Beis Din of the Eidah Charedis people complained that he wasn't a big kannoi. The Satmar rebbe said that anyone can be a kannoi overnight, to become a Talmid Chacham like R' Weiss takes 20 years.
This is exactly the problem today, everyone is a kannoi but how many kannoim have their kanaus defined by the Torah?