Why did scientists suppress the lab-leak theory?

Matt Ridley:

In August 2007 there was an outbreak of foot-and-mouth virus on a farm in Surrey. It was a few miles from the world’s leading reference laboratory for identifying outbreaks of foot and mouth. Nobody thought this was a coincidence and sure enough a leaking pipe at the laboratory was soon found to be the source: a drainage contractor had worked at the lab and then at the farm.

In December 2019 there was an outbreak in China of a novel bat-borne SARS-like coronavirus a few miles from the world’s leading laboratory for collecting, studying and manipulating novel bat-borne SARS-like coronaviruses. We were assured by leading scientists in China, the US and the UK that this really was a coincidence, even when the nine closest relatives of the new virus turned up in the freezer of the laboratory in question, at the Wuhan Institute of Virology.