Trump is skilled at misdirection and deception, and this article's writer, Ms. Giaretelli, either approves of that approach or is easily fooled by it.
What trump tweeted are two distinct and for this discussion, unrelated matters. 
First, despite what a careless reading of trump's tweet might suggest, Schumer did NOT suggest zero evidence of Russian interference in the election- that's just trump's claim, inserted before the Schumer message.
Second, Schumer's point was that the most productive approach to winning future elections would be stronger Democratic Party messaging and candidates (rather than relying upon becoming fixated upon Russia's role in US election).
Schumer's message in no way denies or dismisses the serious matter of Russian interference in the US political process- it's just a more broad, proactive emphasis.
Still, I suppose that trump (with his skilled mishmash talk) and the WE will have their way with uncritical minds and readers.