Part of bikush haemes is to come to an outcome based on the facts and not the opposite and to realize that maybe something unpleasant can have a positive effect.
Prior to being quoted here, I have never seen or heard of this quote from the Mekor Boruch.
A quick online search came up with Mondshine's article (R' Y. Mondshine A"H is not the topic of this thread, so let's not go there now - he worked in the Hebrew University as a librarian and is a known researcher).
Not being familiar with the quote, but being familiar with some history, and my (inside) view of Chassidus (Chabad), the quote seems odd (to say the least). Which is why I was OK quoting not only Mondshine, but bringing it from a certain website that tends to represent only its owner's and editor's point of view, rather than a broader spectrum which exists within the Chabad-Lubavitch community.
I suggest you read רשימת וויכוח מינסק which I linked to above (which corroborates some of the stories from several sources - and does not placate or try to deny that the Bima was carried out on Shabbos). I would love to see sources from the "opposing" side telling their version of the events.
I would also recommend reading
http://w3.chabad.org/media/pdf/899/WqPJ8993112.pdf (paging
@ben89 - are you familiar with these writings about the Gr"a? What sources are you familiar with in regards to the people and events described in this רשימה?).
I don't know what the Tzemach Tzedek said, I wasn't there and I haven't seen any corroboration. Is it possible that credit was given to the רדיפות וחרמות? Possible, as I said before וכאשר יענו אותו כן ירבה וכן יפרוץ including the legal status vis-a-vis the Russian government. But the specifics (which might be an interpretation) saying that Chassidus might have gone "too far" just don't make sense.