Specious argument

The most specious argument put forward is that had Congress agreed to ditch its Muslims and become an only-Hindu party as Jinnah demanded in 1937, partition would have been avoided.

The reality is that Muslims were already talking of Pakistan in that period because Muslim majority provinces were refusing to accept even the Federation of 1935 Act (which did not have a Congress majority at center and no Dominion status forget Independence)

Arrey bhai, after surrendering the right to speak of united nationalism how and using what arguments would a Hindu-only party have prevented a Muslim-only party from walking away with Pakistan?

In 1937 Jinnah was essentially setting the Congress up. Whatever the Congress did, he would have accused it of not doing enough. By giving up on united nationalism altogether and speaking only for and to Hindus as he demanded, Congress would have had no reply to make to his further demands on them and the British.