Notice your own definition does not use the word "always", but rather "often"... could as well be "sometimes" or "occasionally".
She's "tak[ing] advantage of an opportunity to achieve an end", with or without "regard for principles or consequences".
She's an opportunist.
"Always" indicates without exception. In labeling human behavior there are always exceptions.
My point is, even IF she's taking advantage of an opportunity -- an opportunity to do WHAT, you haven't said -- it doesn't mean she's not doing it because she's just as pissed at the double standards as we are. Maybe she got her hopes up that Trump would actually get us out of these never-ending foreign wars, and then Biden comes along to start new ones? Maybe she saw change in our relationship with N. Korea only to have Biden screw that up, and now Rocket Man has tested what? 6 missiles in a little over a week?
Maybe the way Biden is trampling on the 1A via Social Media and MSM censorship of opposing ideas and criticism, giving tons of money and weapons to Ukraine while trying to give the ATF more power to harass legal gun owners here while telling the people to "suck it up" over inflation and oil prices is part of it?
Maybe she realized the decisions being made in DC are no longer part of the Democrat Party's stated platform, but are part of an agenda that she never signed onto.
If we have to trust someone in high level politics, how about naming someone YOU'D trust. Not a new candidate, but someone who's done the job, is electable, and who can "lure" others from that party to join them.
I heartily welcome her to join the Independent Party -- which historically syphons votes from the Democrats.
By your definition, anyone who takes an opportunity to achieve something they want is an
opportunist regardless of motive. Maybe that includes you, too?