You don’t actually consent (per-se) in most cases. Hence the warrant.

If you consented, no warrant would be required.

Consenting to data being collected by a company does not mean you consent to a search by the government of said data.

As noted, the company can sell it however. Which is even easier than a search, which typically requires paperwork.

They can, yes. But this is a legal loophole that the government abuses to circumvent a warrant required by the 4th amendment.

The 4th (and 5th) amendment requires warrants to compel folks to do things they aren’t voluntarily consenting to do….. Not really a loophole per-se.