Meta acknowledged in a statement to The Washington Post that Threads is intentionally blocking the search terms and said that other terms are being blocked, but the company declined to provide a list of them. A search by The Post discovered that the words “sex,” “nude,” “gore,” “porn,” “coronavirus,” “vaccines” and “vaccination” are also among blocked words.
“The search functionality temporarily doesn’t provide results for keywords that may show potentially sensitive content,” the statement said, adding that the company will add search functionality for terms only “once we are confident in the quality of the results.”
Lucky Tran, director of science communication at Columbia University, discovered this himself when he attempted to use Threads to seek out research related to covid, something he says he does every day. “I was excited by search [on Threads],” he said. “When I typed in covid, I came up with no search results.”
Other public health workers criticized the company’s decision and said its timing was especially poor, given the current coronavirus uptick. Hospitalizations jumped nearly 16 percent in the United States last week and have been rising steadily since July, according to CDC data, though they remain less than what they were for the comparable week a year ago. Deaths are less than a quarter of what they were year to year, CDC statistics show.
(OP: Sorry, paywall, can’t find another source yet. Someone got an archive?)
I’d like to believe that Meta is acting in good faith, as you seem to be assuming, but given their history, I just am not willing to put any faith in that.  And I’m certainly not alone in feeling that way. 
That’s fair!
My intention was not to assume good or bad. Their, and other big tech companies, motivations do not matter for the end result to be wrong.
Likewise: Groups of good people, acting in good faith, can still produce bad systems.
I apologize if it sounded like I was maligning you or implied you were being naive; you were simply stating facts, but Meta’s profit motive, combined with their history, in my opinion, negates any assumption or even a consideration of them acting in good faith until proven otherwise.