Because regardless of what people "should" be doing, there's always extra to pick up at this time, and going into denial about it creates problems that last for weeks rather than days.
Eg I live in a block of flats, with a communal bin store for three blocks. It was last emptied 3.5 weeks ago and now it's so disgusting with both overflowing recycling and regular bins that the bin lorry came and went today just leaving it in that state. We are all now going to have to pay the management company an extra fee to clear it, and I'll be storing trash and doing tip runs with my own waste until that happens.
Obviously the immediate problem has been caused by people just dumping stuff in there once the bins got full, but it probably wouldn't have happened if we'd had an extra pickup over Xmas - the rest of the year it's fine, but every Xmas it backs up. It's not even solely caused by my immediate neighbours - I've certainly witnessed people driving into the estate and offloading their trash into our stores, presumably because their own collection schedule isn't adequate at this time of year.
AIBU to think that although yes it would be lovely if we lived in a waste-free world where everyone merrily composted their tiny output, simply pretending there isn't a problem actually creates a much bigger problem that could be easily resolved by just one extra waste collection, once a year?