Communication issues with LDR gf - do they ever work?

Me and my gf are in a long distance relationship, yes I know the pitfalls of how hard these are to manage. See each other once a fortnight. Normally occasional argument, but other than that, all sweet.

Last night I was the pub with a mate having dinner. Was just the usual texting back and forth with my gf, asking how her night was going.
I texted that I was a bit sooky, because I missed her.

Her reply was that I shouldn’t be sooky as there was probably hundreds of people at the pub I could talk to.

Now obviously that threw me a bit, I didn’t suddenly react, but I did raise it, how I kinda was expecting a more softer response(she can be a bit abrupt on occasion with texting). It started this back forth, and caused an argument. She said it was messed up that I was only texting how I missed her, to get a response similar back, and that she said it’s a bit manipulative of me.

She communicated that whenever she says something, like I love you or I miss you, she is saying it because she wants to, not because she wants me to say it back. Which I think it’s silly because if I didn’t say it back she’d most certainly feel a certain way.

Now, am I being a bit of a twat by thinking that’s pretty weird for her to say that?
I think she’s being quite cold personally
Or am I misreading this situation and she’s making a fair point?