Yeah...I don't know. My mum is someone who does this a LOT. She thinks she can say anything as long as she says 'Oh it's a JOKE! I'm only JOKING!' And for 20 years I've asked her not to do it and explained that even saying something mean as a joke is still saying something mean. Yet here I am at 35, and she still does it. Likewise, she'll say mean things to my family about me and laugh about them. She really thinks it's funny to do that. She doesn't comprehend that it's deeply upsetting, and the reason I don't really speak to my family anymore.
I can never for the life of me figure out if her thought process is:
a) she doesn't want me to do it but I don't care, I'll do it anyway and just apologise later, it'll be fine or
b) Oh ok. [3 days later] Har har! Funny joke! Big fat Caitlyn! Har har! And just doesn't understand what she's doing.
So yeah...if anyone knows the answer...it's baffled me for decades.
Interestingly, the other thing I've noticed she does over the years is any time I have something good happen, she'll do everything she can to tear it down and spoil it. I think there's a lot of jealousy there, especially with looks and talent. I've danced since I was 2, and at one point was part of a dance company that performed at the Barbican. The night before our show, she sends me this lengthy email about all the stuff I'm doing wrong to her. I think she did it deliberately to try and ruin my happy, proud experience. (She's still never seen me perform, not even once). I don't recall seeing much about the girls' talents and good qualities. Unless writing cards about how much they love you and you're the best mum ever counts. I don't count the school play because I think AE used that as a weapon against IG, not as something she was proud of, per say. And I think she'd see it more as her achievement, not E's, because acting is her 'talent' that she passed on. "You're just like me!"
I also see AE kind of doing something similar with looks at my mum did to me, like with the height thing. She wasn't openly making fun of E's height, but she was noting it, and my mum does stuff like that. That way, you can't say to her, 'oh please don't say that it's not very nice' - my mum's second favourite phrase after 'I'm only joking' is 'I'm only SAYING! I was just SAYING!' It's very clever really. She'll point negative stuff out and when I get upset she'll say 'I was only saying!' I've definitely noticed a very similar pattern with stuff AE says, but I can't think of specifics right now.