Why is Media Matters allowed to operate as an 501(c)(3) organization when its only objective is political propaganda and censorship of oppisition?

Per wikipedia:

501(c)(3) tax-exemptions apply to entities that are organized and operated exclusively for religious, charitable, scientific, literary, or educational purposes, for testing for public safety, to foster national or international amateur sports competition, for the prevention of cruelty to children, women, or animals. 501(c)(3) exemption applies also for any non-incorporated community chest, fund, cooperating association or foundation organized and operated exclusively for those purposes.

By Media Matter’s own admission they exist to promote leftist propaganda and attempt to stifle dissent, which clearly is the exact opposite of the educational benefit that they claim allows them to remain tax exempt. Those funding the undermining of US democracy shouldnt be allowed to remain in the shadows. The public is entitled to know who is ultimately responsible for the censorship and propaganda.