Imran Khan Unveils New Map That shows J&K, Ladakh as Part of Pakistan

so they're openly annexing foreign territory, though it has been disputed by all three sides since WW2

The conflict started after the partition of India in 1947 as both India and Pakistan claimed the entirety of the former princely state of Jammu and Kashmir with Pakistan recognizing Chinese sovereignty over the Trans-Karakoram Tract and Aksai Chin since 1963.

Pakistan is Chinese ally, it's obvious they're working together against India and will fight together if needed

seems like the Brits made a mistake that they let them have their own countries

The Partition of India of 1947 was the division of British India into two independent dominion states, India and Pakistan. The Dominion of India is today the Republic of India; the Dominion of Pakistan is today the Islamic Republic of Pakistan and the People's Republic of Bangladesh. The partition involved the division of two provinces, Bengal and Punjab, based on district-wise non-Muslim or Muslim majorities. The partition also saw the division of the British Indian Army, the Royal Indian Navy, the Indian Civil Service, the railways, and the central treasury. The partition was outlined in the Indian Independence Act 1947 and resulted in the dissolution of the British Raj, or Crown rule in India. The two self-governing countries of India and Pakistan legally came into existence at midnight on 15 August 1947.

wiki

Pakistan is one of those strange countries where it doesn't make sense to say whose ally they are, or who they are in bed with.

Its 200 million people, for God's sake!

Nothing will ever be more important to them than winning a war with India, even if it is a war of words.

The US? China? Russia? None of that matters to them, except the extent to which those countries can help them against their rival, India.

it is the classic case of 'fences make good neighbors'.

While the whole world is worried about China, Pakistan is worried about India, because India is their next door neighbor!