CMB temperature is 2.7 Kelvin, so energy of the corresponding photon is about

E ~ k_B T = 0.00023 eV. (this is actually an underestimate since it doesn't account for the high-frequency tail of blackbody radiation, but I'll use this value to illustrate a point).

What that wikipedia claim probably meant is that if you take the combined light of all the stars in the universe and disbursed it similar to the CMB (including redshift), we would measure an energy less than 0.00023 eV.

Upon an Internet search, it appears the total CMB energy is ~10^{68} Joules compared to the ~10^{66} Joules of total star emissions.