I don't think that the quote is particularly worrying.

I think the FBI lawyer is pointing out that as the scope of what constitutes a search expands the harder it becomes to establish probable cause in the first place.

I agree with the article, that if 90% of the affected GPS trackers could demonstrate probable cause to get a warrant then the FBI doesn't really have cause to complain (about this one ruling). However, I don't think that invalidates the quote.

I think the quote is literally true and shouldn't be taken as anything but a FBI lawyer talking about the limitations that the agency faces but like the article says the limitations aren't necessarily a bug.

Edit: Clarity

It seems that a certain culture is growing inside law enforcement agencies, one that doesn't respect the spirit of the Constitution anymore, and they just try to use whatever loopholes they can to arrest someone. Even the OWS protesters are being arrested on simple technicalities, without common sense.