A sticking point in the Wikipedia article is beneficial ambiguity regarding Haldane's departure from UCL and the UK.[1] He was a staunch Stalinist and a Lysenkoist.[2] At the time many of his Soviet peers were executed for being "reactionary", i.e. non-ideological. Haldane was well aware and did not condemn the atrocities. His wife disputed him over this and it nearly cost their marriage.[3] Charlotte his wife is negatively portrayed.[1]
[1]
https://en.wikipedia.org/wiki/J._B._S._Haldane#In_India
[2]
https://www.jstor.org/stable/4330841
[3]
https://www.msn.com/en-us/news/world/how-stalin-manipulated-...