The Red Sox pitching BABIP in April was .284, which iis very reasonable.
Know what the Yankees pitching BABIP has been in all of May? .240. But, hey, don't mention that. And the Yankees 85.4% LOB%? Yeah, that's also not sustainable.
Not to mention, he quoted xFIP, not ERA. xFIP is a much better indicator of future ERA than current ERA. It normalizes HR/FB, and takes into consideration BB and K.
And as a side note, the Sox, as a team, have a 33.3 WAR. The Yankees have a 29.5 WAR.
The Red Sox main problem right now is that they are hitting .176 with RISP in May.