Looks like MAN waited to get all their lucrative long hauls in before closing for a sweep.
SNOCLO at MAN was from 0910 -1040
Apart from the SQ which was last to land before the closure, the other "lucrative long haul" arrivals were at 0616, 0643, 0655, 0657, 0703, 0706,0738 and 0813 which was before the snow started coming down hard.
You close the runway when it becomes unsafe and safety over-rides commercial considerations.
When you have had practical experience of closing a runway and clearing it whilst minimising disruption and ensuring that safety is not compromised, please share your thoughts again.