That's totally false. Infection control systems were activated. SARS and MERS did
not spread widely, either. Here's one example from Canada:
>All hospitals in the Greater Toronto Area (GTA) and Simcoe County were ordered to activate their “Code Orange” emergency plans by the government. “Code Orange” meant that the involved hospitals suspended nonessential services. They were also required to limit visitors, create isolation units for potential SARS patients, and implement protective clothing for exposed staff (i.e., gowns, masks, and goggles). Four days later, provincial officials extended access restrictions to all Ontario hospitals.
https://www.ncbi.nlm.nih.gov/books/NBK92467/
That same article discusses how WHO communicated during the process. The reaction to SARS was not simply let is spread and see how it goes.
This paper discusses the response in Hong Kong, which included hospital infection control, isolation and contact tracing.
https://www.scopus.com/record/display.uri?eid=2-s2.0-1244426...
Contact tracing is standard even for outbreaks of diseases as common as measles. Page 6 of this Alberta health document for measles control from 2018 discusses how to respond, including contact tracing.
https://open.alberta.ca/dataset/cddcf8b0-9193-4fd7-aa49-def3...
Public health measures aren't that visible if you aren't that involved but it doesn't mean they don't exist.