What is funny about the use of sanitary products?

My dad would often do the weekly shop alone (my mum can’t drive and/or was working a late shift) and I’m one of two girls so at one point in all our lives, three people in the household were in need of sanitary products. My dad didn’t give a shit and bought all the supplies like a grown up. So I expected it to just be normal. Fortunately my husband is fine with buying period products when shopping alone too and his only issue was making sure he got the stuff I preferred. I think I did get a few phone call the very first time because he felt there was too much choice, and tbh in some shops there’s loads! Different brands, types etc. I cut a bit of slack there because most girls at first just end up using what their mum (or other relative/guardian) has and the first time you shop for yourself and realise you could choose a different thing…it’s a bit overwhelming! But getting funny about it in general is as weird as getting funny about having to buy toilet roll. We’ve all got bodily functions.