It doesn't seem rational to me either. He was caught red handed but won't admit he directed the payments. Maybe it's just his nature to deny everything to the end. That and all the lies claiming false credit and attacking every opponent are the main reasons I don't think he's a credible President.
The true things, that weren't hacked, would have been reported on anyway for the electorate to consider when they voted. Even the hacked stuff you might say was worth knowing if it wasn't from only one side. If they had released Trump's tax returns and disclosed the TT meeting and attempts at a TT Moscow then we could disregard their inference more as a public service. The way things occurred though shows that they wanted to attack Hillary while having influence on Trump once he was elected.
And if you consider Trump's actions since then he was either a willing participant or someone who is afraid Russia will disclose all the information they do have on him. Right now they can make any claim as to the subject of their private meeting and Trump is such a liar nobody will believe any counter argument he would make.