I'm with you. If you're navigating to a website, you should open the web browser. The app shouldn't monitor or inject crap when I'm going to an unaffiliated site. The worst offenders are the ones that force you to enter credentials for a 3p account with an in-app browser.
That said, it's a huge UX failure that navigating between the web and an app is so broken. That doesn't mean that it's motivated to break the fundamental models of the web. Long term it does much more harm than good. How do you teach non-technical users good practices if developers circumvent these barriers anyway? "Trust us, we won't steal your Google account" is not exactly reassuring, but ok say that you trust a reputable app to do that. What happens when the user normalizes this behavior and a less reputable app does the same thing? Obviously many users will have no idea of the risk.
That said, it's a huge UX failure that navigating between the web and an app is so broken. That doesn't mean that it's motivated to break the fundamental models of the web. Long term it does much more harm than good. How do you teach non-technical users good practices if developers circumvent these barriers anyway? "Trust us, we won't steal your Google account" is not exactly reassuring, but ok say that you trust a reputable app to do that. What happens when the user normalizes this behavior and a less reputable app does the same thing? Obviously many users will have no idea of the risk.