This doesn't surprise me at all. She's an American politician, with presumably high ambitions - supporting Israel strongly is the only logical thing for her to do (no matter here personal views, which of course may well be very pro-Israeli as well).
What does surprise me is the fact that she was a Republican as late as 1996, according to the article. Warren was near 50 at the time, so it's hardly some "youthful mistake" either. It's funny though how she uses that old tired (and generally untrue) cliché of "I didn't leave the party, the party left me" (paraphrasing her, of course). A strange choice for Hero of the True Leftists.
I don't know where you got this from... in her memoir she makes it very clear that she switched from because she did research on the causes of bankruptcies and figured out the Republican excuse of irresponsible spending sprees to be BS. Also, I think (though I'm not sure) her family was ancestrally Republican.
Also, True Leftists universally despise Warren
Wait, aren't True Leftists her fanbase?