Your translation is not in colloquial English. It should read: People have a right to medical/fair treatment. (I am an ESL teacher.)
What is this supposed to mean? Has a right to be treated fairly? This is a very strange statement.
It's also hard to know in Portuguese version. I would guess "tratamento" refers to 'health care' or perhaps a 'fair treatment'...
No way to say for certain. An example where it makes more sense:
"A população tem direito a tratamento de saúde adequado" = The population is entitled to adequate health care.
This is a strange sentence. An adjective is missing. Fair treatment? That's what immediately comes to mind. Equal treatment? Just treatment? Humane treatment? It's really weird as written.
Or a health treatment?
Should this not be "à tratamento" rather than "a tratamento"?
I thought tratamento was masculine too..
Yes, as tratamente is a masculine word. you can't use "à", which is specific to feminine nouns.