Why does the mobile app use a completely different domain? Who designed this thing?
It's not easy to be 100% vigilant 100% of the time against attacks deliberatly crafted to fall for them. All it takes is a single well crafted attack that strikes when you're tired and you're done.
Password managers themselves have had vulnerabilities, browser autofill can fail, and phishing can bypass even well-trained users if the attack is convincing enough.
Good hygiene (password managers, MFA, domain awareness) certainly reduces risk, but it doesn’t eliminate it. Framing security only as a matter of 'individual responsibility' ignores that attackers adapt, and that humans are not perfect computers. A healthier approach would be: encourage best practices, but also design systems that are resilient when users inevitably make mistakes.