To me, her harping on about being a size 18 is actually quite annoying as I don’t view 18 as ‘plus size’ as such since most high-street brands go up to an 18 as standard. It’s not like she’s facing a more limited choice, a limited range or having to go to specialist retailers, which is usually the case for anyone who needs a size bigger than 18. It feels like a bit of a humble-brag, saying ‘I’m big but I’m not that big’ and pointing out that she might be ‘plus-sized’ she can still shop on the high-street. It feels a bit petty to say but it’s irritating to have someone using the ‘plus size’ label but not actually be promoting fashion that actually works or is sold in a size that will fit many plus size women.
i swear that's exactly the reason why she constantly emphasises the fact that she's a size 18. the uk average is a size 16, so she's literally *just* over the average size - therefore she can class herself as wearing "plus size" clothes, and stay on that body confident plus size bandwagon, which will increase her followers, since people will follow her expecting true plus size style advice. despite classing herself as "plus size", she can still reassure herself that she's the smallest plus size possible - which obviously boosts her self esteem, because she very clearly ISN'T body confident, and a great deal of her self worth is based on her clothes size. as you say, the majority of shops stock a size 18 as a regular size - it's hardly a size that's difficult to get hold of! if she truly was body confident, and a us size role model, she'd be perfectly happy to admit when she has to size up in certain clothes and buy a size 20 or 22. she's happy to tell everyone that she WAS a size 22, but she clearly feels insecure/ashamed of her weight gain - which, in itself, is perfectly fine, but not when you're labeling yourself as a body confidence role model, whilst lying to the people who follow you!
equally, i doubt many "plus size" women are actually following her, since she happily buys all her clothes from high street stores which often don't stock inclusively sized clothes, and it's never a struggle to find clothes in her size. plus if someone felt self-conscious about their weight, and was following babs as a way to increase the ability to feel confident and comfortable in their body, i doubt having size 18 repeatedly shoved in their faces would help them feel any better. it's kinda like her "i'm so lucky" spiel - "i'm so lucky! i wear vaguely" plus size"clothes, but i'm ONLY a size 18!" having truly plus sized followers probably makes her feel better about her own body, in a twisted way - which is why she happily flaunts her body all over SM - rubbing her small" plus size" body in everyone's faces, while simultaneously receiving endless comments about how she's "gorgeous" and "amazing" and "beautiful" and "hot" - a confidence boost from the swooning babettes.