The latest Democrat defenses boil down to this: the Trump surveillance story is a distraction from the Russia investigation, and the surveillance was "incidental". (The Democrats have discovered a new official word they like).
The FBI and CIA said last year they found no evidence of contact by the Trump team with the Russians. The Dem's keep demanding further investigations anyway, as it makes it look like the Trump team is guilty. Meanwhile, we have this "distraction" that is actually a crime at the highest levels of the Obama administration.
As for incidental, if they were surveilling the Russian ambassador, for example, and came across a conversation with Flynn, that would be incidental. Multiple intel reports with Flynn's name unmasked is not "incidental". It's a pattern. Multiple reports with multiple team Trump members unmasked is not "incidental" any more than winning the Powerball lottery six times in a row.