You'd be wrong. The police hadn't announced themselves, so as far as the victim could be concerned, there were strange people sneaking around in the backyard, peeking into windows and vehicles. Every reason for her to assume they're criminals casing the place, and to arm herself against a potential home invasion.
She had every right to arm herself.
Worse, in Texas they have Castle Doctrine, so she should have pre-emptively shot the officers. It would have saved her life, and she'd have been in the legal right to do so, per Castle Doctrine.
The reason some of us get so angry about this shit isn't because "yeah, dead cops", it's because cops like this have continuously demonstrated that the police are the enemy of the people, and this provides reasonable grounds for defending yourself from the threat they inherently pose to you. Better to take the shot and survive to stand trial than to let yourself be murdered, as she ended up doing. Cops acting like this, and departments defending them, and people doing the whole "the police have no duty to protect" thing, this all translates to "cops are your enemy, treat them accordingly". And that makes things far more dangerous for police officers.