If a bio research lab is accidentally allowing the public to come in contact with anything it is studying, this is something we need to
1. investigate
2. identify
3. prevent
Saying "it's possible this could have happened anyway" is not meaningful. I would prefer we identify how it did happen. If a lab leaked it, this would inform future discussions on what lab practices and research projects have acceptable risk/reward.
Ignoring the possibility this leaked from a lab until you have bulletproof evidence is nonsensical, particularly when investigator access is restricted. This, more than anything, is the point the article is making. Lab containment failures have a well documented history.