Why am I being punished for moving to the USA?

I am from Toronto and left for economic reasons. When I graduated with my education degree and started my job search as a teacher, the only full-time teaching jobs in Toronto were for French Catholics. Believe it or not, Toronto has four publicly-funded school boards and only one of the four is English speaking and secular. Two publicly funded boards are religious and two are French. This in city where French isn't close to being a top 10 language. Long story short, between lack of affordable housing and lack of options in the job market, I jumped at an opportunity to teach full-time across the border -union job with a pension and public healthcare that actually far exceeds what I had under OHIP. I say all of this just to explain why I left. It had nothing to do with hating the city where I was born and raised. Far from it, I love my city.

Long story short, I now have a U.S. passport and enhanced driver's license and a NEXUS. I travel back to visit my family and friends. While I do like the separation of church from state and the concept of public secular school system that does not divide a population based on religion and ethnicity, these are personal views. I do not share them at the border. Yet when I am asked why I left Canada, as if that is relevant, or what I am doing living in the states, these are the thoughts that enter my mind as responses. Of course I don't dare share them.

My passport isn't a political statement. It's a travel document. Why am I subjected to question after question after question when entering Canada.? They aren't relevant questions and the demeanor has been rude on multiple occasions. My passport says I am born in Toronto. I also have Canadian ID and a Canadian birth certificate. It's my right under International and Canadian law to enter Canada. It's not enough to say I am visiting family? Why do I need to say for how long or tell these officers where my elderly mother lives? What if I change my mind and spend longer or decide to stay with a sibling? Also, I am a citizen, there is no time limit for how long I can spend in Canada.

Is anyone else having an experience like this? It's almost like there is a directive to mistreat U.S. Citizens born in Canada like we have done something offensive and wrong. I have a more pleasant time entering the USA and even Mexico, where I also travel. Has it always been like this?