It’s quite logical for a man to shrug off the importance of electronic interference in an American Presidential election by a foreign government, if the interference is what allowed the man to be elected.
Donald Trump is many things, but he is not stupid. If he can divert attention from the Russian interference, he will take power. Once in power, then of course he will neutralize investigations and the election manipulation will have been successful. He will owe allegiance to the country which helped him to be elected, and the maneuver will have worked nicely for both sides.
Mr. Trump excels in diverting attention from important issues until they are moot. For example, we have forgotten he refused to make public his tax records. He will do the same with election tampering by Russia.
The USA has interfered in elections of other countries, “promoting” a candidate which it prefers for political and economic reasons. Interesting karma.