Fishing trawlers don't capture everything they catch: Most of it gets thrown back. This is all semantics, but without more context for the word "capture" (like, why it wouldn't be legal to capture data you'll never look at), I don't think it's patently absurd to read the term in a way that makes reasonable intelligence work possible.

What if they only buffered the data for a few seconds while picking out the "good stuff"? A few hours? Where is the line?

I have no reason to think that they wouldn't keep all of it, forever, period. Or at least retain a long enough window to render this statement pointless.

If you think the NSA has no effective oversight and is lying to the FISA court or the President about what it does and doesn't do, you have bigger problems.

Old fashioned police work? Only gather data with a warrant?

The NSA isn't a domestic law enforcement agency. You're thinking of the FBI.