I have a question, and this is a real question, I'm not trying to be a dick here.
Suppose that Katie is a very large, very unattractive woman, and the meaning behind the statement isn't, "I'm going to sit where I can take advantage of the low cut dress", but "I'm going to sit as far away from her as possible", is it still sexist?
Same statement applies: if you say that sort of thing only to women, yes, it is sexist. If you treat both men and women that way equally, you aren't sexist, just an asshole.
Sorry about the downvotes, it's a legitimate question to me.
There's worse out there (well, that's just about always true), but sure: that's sexism.
It's pretty obvious if you take it apart a little.
You're singling out the one woman in the room, commenting on her physical characteristics, and saying that (presumably because of those physical attributes) you're going to sit next to her.
Now, why would you want to do that? Sit next to this person purely based on her gender and physical attractiveness?
Well, obviously you're not singling her out as the most expert person in the room, or anything else remotely related to your actual purpose for being there (I'm imagining this in a work environment).
Nope, you're sitting there to hit on her. You've already started, with the compliment. Possibly only very politely, but will she trust you to stop there? And will she now have to assume you're casting sidelong glances at her breasts when she points up at the whiteboard during the discussion?
And since this is a work situation (not a social one), she doesn't even have the option to excuse herself and go talk with other people if your advances are unwelcome.
It would make me uncomfortable. I wouldn't say anything, because I'd be told to 'lighten up'.
Why would it make me uncomfortable? It would subtly remind everyone in the room, including me, that I'm different. And it would place an (unintended, I'm sure) emphasis on my physical attributes, which have nothing to do with my ability to design or program software.
It's bullying and harassment and would be covered in UK employment laws.
One can imagine such comments causing Katie distress or stress. Employers have a legal duty (which has been tested in courts many times) to protect their employees from harm (and that includes stress) in the workplace.
It is quite possibly sexist; there's not enough information to say.
Suppose that Katie is a very large, very unattractive woman, and the meaning behind the statement isn't, "I'm going to sit where I can take advantage of the low cut dress", but "I'm going to sit as far away from her as possible", is it still sexist?