Who cares if it came from a lab, there are zero consequences to anyone whether it did or not, and it's the least impactful detail of what has happened. "Allowing," debate on the disease origin is a cynical switcheroo.
1) So we can learn and mitigate the risks of something similar happening again.
and
2) In the event that the virus was leaked from a laboratory, the world would like to send the lab a small invoice for costs incurred and damages.