An argument could be made that they're also stronger at #3 TE, but I do agree mostly.
You could look at it a few ways: With no picks after the fourth round (yet) this year, BB is using free agency to stock up on depth, perhaps more so than usual.
You could also just say this is the usual BB rummaging through the scrap heap and pulling out some intriguing finds. Several of these signings could go on to make significant contributions; it's also possible that at least half of them don't make the team.
Finally, back to the draft: You could get excited and say "this is the year they move up for an impact player because they got their depth in free agency," but I'll only believe that when I see it.