I don't think anyone is saying you're doing something wrong. Most people, myself included, just seem to want some further information as they're curious why the matches you're in aren't backfilling. Knowing what mode you're experiencing this with would be very helpful, since not all of the backfill with bots requires more human players before they'll start.
For example, I play at very strange hours quite often myself (crossplay off as well, so it's an even more limited pool of players), but as I predominantly play Breakthrough, matches will begin with bots after about 2 minutes. However, if I want to play something like Strikepoint, then I'll need to either turn on crossplay or wait and try again during peak hours.