You're both right. In grammatically gendered languages, various situations and context are present. Sometimes, people get worked up on a non-issue (like the latinx example other commented). Other rules have a more debatable impact, like the famous "in groups, the masculine prevail".

Interestingly, other approaches existed in the past like the rule of proximity where the gender of the closest element will dictate how the verb and adjectives will be written.

Languages are an ever-changing thing. I think it's healthy to propose and discuss grammatical changes if it makes sense, but everyone should be aware of what they are actually talking about.