I have a question regarding this video

<https://www.khanacademy.org/math/algebra/exponent-equations/exponent-properties-algebra/v/adding-and-simplifying-radicals>

He said that $\sqrt {x^2}=|x|$ has to be the absolute value of $x$ because $x$ can be positive or negative, which makes sense but why is $\sqrt 4= 2$? Shoudln't it be $|2|$ too? Because $-2 \cdot -2 = 4$ and $2 \cdot 2 = 4$.