I have empathy for you, Stacey. It must have really shaken you up, and what a disappointment from what you had in mind. It's not what one expects, for sure.
Some may say "you should have known better", but this really is a dramatic change over the past year. I had experienced the first (
***
) of your story about 1.5 years ago, at 2:00 AM. Same experience waiting in the "cordoned off area". However, the immigration officer - possibly a higher level manager - did allow me in with a warning that next time I would need a proper visa or be denied.
I was not angry at the time, but a bit unsure what would happen if I had been denied. When I was ultimately allowed in, I was massively grateful for the officer that let me in. I promptly applied for and received a suitable visa since. We must always keep in mind that entry into foreign country is always at the discretion of the immigration officers, and they can deny entry for any reason.