Isreal is a state though, it isn't all of Judaism. The fact that there are Jewish people protesting against Israel should be a clue.
Also, you can support Palestinians without supporting Hamas. I know there are the idiots that do genuinely stand behind Hamas thinking it's simply another Palestinian group, but the sensible people stand behind the civilians suffering, not the group that's helping to cause this.

So yes, you can dislike Israel without disliking all Jewish people. And you can support Palestinians without supporting Hamas.

The Western Liberal in Question: