No, he's not a Modernist. He's got other issues surrounding religious indifferentism and ecuмenism.
Strickland's entire contention with Bergoglio was that Strickland held the Bergoglio was not being faithful to the Deposit of Revelation, whereas Bergoglio countered by claiming that Catholic doctrine could change (which is essentially what Modernism is).
People throw around the term Modernism without any real understanding of what it actually means.
Now, I haven't watched the Dimond video, so I don't know if THEY used the term Modernist, or that was just attributed to them by the OP.