This is a bit disingenuous. If you install Chrome, you install Chrome and all it's parts. They don't ask your consent for individual parts because that would be absurd. If you don't want Chrome and all its parts, don't use it.
If you're okay with 4GB being added, where would you draw a line? What if it downloaded a 40GB file? 400GB?
Lately Firefox has been getting better, but I still prefer Chrome for almost all my needs, so I stick to it. This barely even makes a difference to me. If it was 400GB however it would make a difference to me, and I would make more of an effort to switch to something else.