If you think about it, it is shocking that Korach joined forces with Datan and Aviram in his campaign to usurp leadership. Korach had a distinguished reputation, as Chazal (the Sages) explain, and he presented his case by way of (very flawed) doctrinal arguments, trying to persuade the masses that his theological position was correct. In stark contrast, Datan and Aviram had a very checkered and disreputable past of nasty confrontation and shameful instigation.
As Rashi explains, based on midrashim, it was Datan and Aviram who were violently fighting with each other in Egypt when Moshe tried to stop them (Shemot [Exodus] 2:3); it was Datan and Aviram who badmouthed Moshe to Pharoah, thereby almost causing Moshe’s execution (ibid. 2:15); it was Datan and Aviram who violated the command not to leave over any manna until the next day (ibid. 16:19-20); and as Midrash Ha-Gadol (Bamidbar [Numbers]16:1) states, it was Datan and Aviram who complained at the shore of Yam Suf (the Sea of Reeds) about having left Egypt and who sought to return there (Shemot 14:11-12 - v. Rashi on v. 12).
Why in the world did Korach join forces with Datan and Aviram, whose very compromised past and quite negative reputation would surely not have served his professed ideological campaign well?
How could people who were known for their belligerent personalities and violations of Torah bring prestige to what Korach promoted as a grassroots religious drive founded on positive principles?
Why would Korach tarnish his movement by aligning with known troublemakers and negative forces?
The answer is that despite Korach presenting his agenda as an ideological crusade for the betterment of the masses, in truth it was a self-serving power grab motivated by jealousy and personal ambition; the ideology was a mere front and a ruse to draw pubic support for what was nothing more than an egocentric stunt. As such, Korach needed loud voices and strident personalities to amplify his message and force Moshe into a position of weakness and concession.
Datan and Aviram were the perfect characters for this. They were the ideal “hit men" and the best people to catalyze a mass movement against Moshe Rabbeinu, escalating matters to the point of surrender and collapse.
It is not surprising that throughout Jewish history, those who sought to challenge the Mesorah (Torah tradition) typically launched their campaigns by professing lofty ideologies that purported to enhance or ennoble Judaism, whereas the reality is that these deviant movements’ true aim to was to dilute and tear down Torah values and observance, usually with an underlying motivation of opportunism on the part of those involved.
By including Datan and Aviram in his uprising, Korach in effect exposed his campaign for what it really was - a self-serving power grab, in which Torah and Torah leadership were contested and defied by ostensibly lofty religious philosophies, all in a base effort by an illegitimate and greedy player to undermine the system and seize power.
May Hashem continue to illuminate our path, provide us with true Torah leaders, and enable us to realize when people are seeking to subvert Torah values while professing to enrich them.