Thanks for the source.  First, let's refresh our memories with a quote of the questioned statement.
"They promised to oppose everything Trump wanted regardless of qualifications."
Now let's read closely.
"he'll vote against nearly all of President Donald Trump's cabinet nominees"
So it is not all the appointees but "nearly" all.  If you were talking about appointees its a reasonable mistake.  Equating the statement to oppose all Trump's appointments to "everything Trump wanted" however is an unreasonable extrapolation that applies to more than just the appointees.  I don't see it as supporting a blanket statement of general obstructionism.
However, you also claimed that the opposition is "regardless of qualification."  In fact, Schumer states it is BECAUSE of their qualifications, or lack thereof, that he oppose them.
"The nominees "have repeatedly shown they will not put the American People or the Laws of our nation first, and I will vote against their confirmations," Schumer wrote."