Because the French and British were resolved to give Hitler and Germany parts of Czechoslovakia because he threatened war otherwise.
They were punked and Maxim Litvinov, as the Foreign Minister of the Soviet Union, wanted Hitler and Germany to pay a heavy price for threatening war against a tiny defenseless country.
What he said here in 1938 forcasted the eventual war that would have to be fought if Germany was allowed to get a away with it.
They dismissed him and close to a 100 million paid with their lives, a lot of them his countrymen.
source: my studies/research
Alexander Litvinov died in 1932.
Alexander Litvinov was born in 1853.
Pavel Litvinov was born in 1940.
Sergej Litvinov was born in 1986.
Dmitry Litvinov was born in 1854.
Dmitry Litvinov died in 1929.
Victor Litvinov was born in 1910.
Victor Litvinov died in 1983.
Juri Litvinov was born on 1978-05-06.
Vitali Litvinov was born on 1970-11-17.
Sergey Litvinov was born on 1958-01-23.
Maxim Litvinov died on December 31, 1951.