Insulting a car (or any other thing or person!) by referring to it as “girly,” or something similar, and thus perpetuating the misogynist notion that anything associated with femininity is inherently inferior, is sexist as hell.
I’ve heard people excuse this with “I’ll insult my car however I want!” (using my gender as the punchline? how sweet, do you say racist things about it too?) and “Oh you don’t count though, you’re one of the cool ones!” (don’t even get me started on the Cool Girl nonsense) and/or “free speech!!” (that’s not how that even works unless you think I’m capable of jailing people).
None of those void the fact that the statement is still sexist as hell, so don’t be surprised if I roll my eyes, judge the hell out of you, and/or give you what-for if I’m in a really shitty mood due to dealing with this (among other things) in a constant tide of bullshit for about 25 years now. My own boss, who is generally a very awesome person, dropped this shit the other day and I gracefully excused myself after he doubled down on it and that used up about all the patience I have for this month.
If you want any of this explained further and can ask without being a jerk, I’ll try to help.
Some freshly washed vehicles that just so happen to belong to this sorority alum for your time: