Take on the post-season NFL signing

One thing that has always bothered me a not he NFL is that the league
allows teams to sign free agents into the playoffs. I get that it is a
brutal sport but I feel like a team shouldn't be able to remake their
roster that late into the season. Take the Steelers who may have
lost superstar and potential gag-ball and leather pants wearing
running back Le'Veon Bell to a nasty knee injury. The rumors around
are that the Steelers will sign recently released veteran RB Ben Tate
who certainly has more talent than anybody else on their roster. How
long is it that a team releases a top kicker right after their season
ends knowing they won't resign him and he immediately signs onto a
roster making a playoffs push. The way that Josh Gordon has acted,
it wouldn't be totally shocking for the Browns to cut him now and if
they did what playoff team would not immediately add him to their
roster for a quick rental???
Maybe the NFL can lock rosters but expand their practice squad.