As noted, check-in is 3pm - so anything earlier is a courtesy.

Keep in mind with checkout being usually 11am or 12pm, housekeeping has to clean rooms. Housekeeping usually updates the computers when they're done with a floor - not each specific room.

Also, I'm guessing you were at a Residence Inn or a TownePlace Suites? The rates definitely vary by length of stay & they tell you pretty clearly that your rate may change based on early checkout.

I don't think this guy needs to be coached on his work ethic and it doesn't really sound like bad service to me.