Why don't Android apps clear their own caches?

I took a look at a couple social media apps I have installed and realized over the course of a month and opening them maybe once or twice a week they've managed to accumulate a combined 1.4 GB.

Does anyone else find this unacceptable? And secondly, why are they not clearing their own caches?

I can understand Android not doing it automatically, that could cause problems. However, a good app should certainly cache data when possible but only for as long as it's relevant. Keeping an entire stream of photos from a dashboard, for instance, seemingly forever, seems to me to be just plain stupid. Installing an app cache cleaner seems an equally bad idea as Android doing it automatically because again, some apps have caches they need and that don't get excessively bloated with time. I'm thinking banking apps, messengers, things like that where clearing it could cause issues or at least slow things down as it resyncs.

So what's the deal? Is this just not a function an app can have? Is an app allowed only to store a cache but not delete items from it? Or are developers just being lazy here and eating up my storage just because I scrolled through some photos a month ago on a dashboard now so ridiculously filled with newer updates I'll never need to draw on that cached file again?