Its easy to understand. Free satoshis. People are and always will be greedy. It's the only working BTC faucet out there, and people, especially people from 3rd world countries, will spend months farming it.
Regardless of the reputation, if the withdrawals work, and they do, they will use it
That's simply not true - there are other faucets that are not just faucets (they have various additional earning opportunities) that still work and you can earn something if you have active referrals. I just looked at one such faucet and there was $20+ waiting to be withdrawn - it's not much, but I didn't have to do anything for it.

I dunno, i tried hundreds back in the day, and FBC was the only one that just gave something. Others, at least in my experience, always demanded some adds to be watched, or surveys to be filled, which weren't worth the time to be honest.
And majority just had too much minimum withdrawl, you had to come back daily for years to get anything out