nobody thinks Obama literally tapped Trump's phone line, even Trump went on to explain what he meant by that. We already know some of the phone conversations at Trump tower were monitored, the DOJ already admitted that. It's just a matter if it was politically motivated and was the unmasking of the names of the people monitored politically motivated or a matter of national security.
Why you are bringing this up again I don't know. If they wanted to really deny what Trump said they would not use such lawyer speak about a wiretap, in 2017 you don't wiretap people's phones.