Agender (one word) uses the "a" prefix to mean without.
A gender (two words) is generally a collection of common traits, ideas, or actions attributed to a group. Almost like a genre of music, or tv. Often, but not always, a person gender and sex match.
That depends "when" and "where" you ask. What is considered to be masculine in the 1400's in the Netherlands will likely differ than what is considered masculine in Korea in the 1800's.
Just like Pop music from the 1920's sounds different from pop music from the 2020's, or pop music from India sounds different from pop music from China.
Because some political strategists realized that it is often easier to get votes by taking advantage of people's hatred of "the other" instead of actually trying to improve things.
The article brings up Danielle Smith, a Canadian right-wing politician doing just that. Using the law to harm "the other", and using hate to get votes. Danielle's policies won't allow children to be called any name other than their legal first name at school without parental consent. This is basically designed to but kids into harm's way, despite claiming to be very "think of the children". The type of parent that a child hides their chosen name from, might just be the type of parent to kick them out of the house as a teenager.
Some "Roberts" turn out to be "Bobbys", some are "Robs", some are "Bobs", some are "Robertas", and some stick with "Robert". They all have a different feeling to them, mostly because of whichever society this person lives in. The correct response is "Okay" and to call them what they would like to be called.
Side note: her first name is not Danielle. So, she should understand that sometimes a name just doesn't feel right, whatever the reason.