I recall Yishayahu Leibowitz's comment when he notes that the paragraph that preced Korach is the parsha of Tzitzit where the people are also called holy:
"... in order that you may remember and perform all my command AND YOU WILL BE HOLY TO THE LORD."
Yishayahu Leibowitz puts it in the following way:
"The difference between these two perceptions of 'holiness' is the distinction between religious faith and pagan worship. The holiness of Parshat Tzitzit is not a given assumption but a task. There we are not told, "You are holy", but a demand is made to "become holy." But in the religious consciousness of Korach and his followers, "The entire congregation is holy." Holiness is something bestowed upon one.
The distinction between the two concepts is deeper still: ... In Parshat Tzitzit, holiness is expressed in the most sublime aspect of the life of faith and the religious mindset of man; that he is required to accept upon himself a task. Nothing is promised or assured. He is simply charged with a demand ... But, in the holiness of Korach and his group ... man frees himself from responsibility, from the mission with which he is charged and from the obligation to struggle." (Notes on the weekly Parsha pg.96-97)
2. Nonetheless, it is interesting that there may appear to be some truth in this egalitarian approach. I think from our modern perspective, we also have a difficult time understanding priesthood i.e. religious ritual leadership as restricted to a particular family or tribe. We value equal opportunity. Do we truly understand why the Kohanim and them alone, are selected as Aharon's descendents? Would a system of "bechor" with every tribe and family represented be so wrong - and don't we know that the priesthood was certainly open to corruption as was seen during 2nd Temple times.
Maybe there is some truth or sanctity here in the argument of the 250? And indeed certain fringe elements of the story do indicate that theer is at least some substance to their acts in that the firepans (of the 250) are "raised" (17:2) "for they are sanctified." Their act did have some residual sanctity. It was not all blasphemy. It was holy! Does this signify a kernel of truth in their motivation, their cause? See the Netziv who suggests that the group of 250 were Tzaddikim and their motivation was pure (if mistaken.)
3. Why did the 250 leaders agree to the ketoret (incense) test at ENTRANCE to the Mishkan? Why not INSIDE the Mishkan? Is it not a recipe for failure? After all the Ketoret is brought inside the Mishkan!
a. They were fearful of the inner chamber of the Mishkan. They were concerned not to enter inappropriately such as the acts of Nadav and Avihu. This was an exercise in caution.
b. Their bringing ketoret OUTIDE is a reflection of their call for access, for deregulation, for lowering the entry requirements and quotas. Their aim is to bring the Ketoret to the nation! Bringing the ketoret in the "hidden" chamber is an insult to the nation. They don't want to separate from the nation. They want to be connected. Bringing the ketoret OUTSIDE is precisely what they are about.
4. Moshe and Aharon's role and conduct in the parasha is nothing other than outstanding. They have suffered incredible personal attack and yet, twice in the parasha , God offers to destroy the nation (see 16:21 and 17:9) and Moshe and Aharon, despite the fact that they may have felt hurt by all the wranglings, refuse absolutely to "allow" God to decimate the nation. TWICE God tells them that they should remove themselves from the sinning throngs. each time they refuse.
Moshe and aharaon show themselves as the true champions of the nation, rather than Korach and his group who each seem to have a personal agenda clothed in idealism.