Whataboutism is excusing bad behavior by pointing to another's bad behavior. Rooney didn't say, "the next time the MSM spreads fake news, remember that Trump did it". He said "the next time someone complains about the MSM spreading fake news, remember that Trump lies." The more rational interpretation is "the next time someone complains about the MSM spreading fake news, remember that the person telling you that the MSM spreads fake news lied 7500 times in two years."