OK, but according to transfermarkt that's you up to 38 senior players. Even if a few aren't really PL standard that's not really needing bodies. You list 6 injuries and the other 4 are just players you don't really want- it doesn't mean they stop existing. To compensate for the 6 injuries you've now signed 7 players in January, which in the process has meant that more players have to be de-registered.
Look, there's no rules against it, it's a bit harsh on the guys who will be twiddling their thumbs but they still get paid I guess. You must surely be able to see why everyone else in football is raising an eyebrow though, it's unusual to have such a big squad of senior players AND then to go out and snap up a new one every time someone gets injured. But if you stay up it's worked I guess and as we will testify better too many than too few!