They just could not stand it anymore. trumps actions force action.

"Scientific American has never endorsed a presidential candidate in its
175-year history. This year we are compelled to do so. We do not do this
lightly.

The evidence and the science show that Donald Trump has badly damaged
the U.S. and its people€”because he rejects evidence and science. The
most devastating example is his dishonest and inept response to the
COVID-19 pandemic, which cost more than 190,000 Americans their lives by
the middle of September. He has also attacked environmental protections,
medical care, and the researchers and public science agencies that help
this country prepare for its greatest challenges. That is why we urge
you to vote for Joe Biden, who is offering fact-based plans to protect
our health, our economy and the environment. These and other proposals
he has put forth can set the country back on course for a safer, more
prosperous and more equitable future.

The pandemic would strain any nation and system, but Trump's rejection
of evidence and public health measures have been catastrophic in the
U.S. He was warned many times in January and February about the
onrushing disease, yet he did not develop a national strategy to provide
protective equipment, coronavirus testing or clear health guidelines.
Testing people for the virus, and tracing those they may have infected,
is how countries in Europe and Asia have gained control over their
outbreaks, saved lives, and successfully reopened businesses and
schools. But in the U.S., Trump claimed, falsely, that €œanybody that
wants a test can get a test.€� That was untrue in March and remained
untrue through the summer. Trump opposed $25 billion for increased
testing and tracing that was in a pandemic relief bill as late as July.
These lapses accelerated the spread of disease through the
country€”particularly in highly vulnerable communities that include
people of color, where deaths climbed disproportionately to those in the
rest of the population."

https://www.scientificamerican.com/a...ses-joe-biden/