It is, admittedly, a little duplicitous. The best answer, I think, is that it doesn't much matter.
What is the nature of the "-" in this expression.
x - 5 = 2 -- Here, it appears to mean SUBTRACTION
If we now subtract 'x' from both sides:
-5 = 2 - x -- That same "-" has magically changed to a NEGATIVE SIGN.
If I write it like this:
-(5) = 2 - x -- Now it appears to mean MULTIPLICATION BY -1.
So what...
From either of the first two expressions, what happens when we add five to both sides.
x - 5 = 2 ==> x = 2 + 5
- 5 = 2 - x ==> 0 = 2 - x + 5
Okay, whichever one it was on the left, it has gone away and both resulted it ADDITION on the right.
Have I convinced you?
Some symbols have multiple interpretations. Sometimes it matters.