Why is pseudorandom OTP (P-OTP) IND-CPA insecure
The game you stated is not the IND-CPA game, it is the IND-EAV game, where the adversary is given only the challenge ciphertext and is asked to guess the message being encrypted. In the IND-CPA game,the adversary is given access to an encryption oracle that can encrypt arbitrary messages of his choice.

The main reason why P-OTP can not be CPA-secure is because it is deterministic, that is, if you encrypt the same plaintext twice you'll get the same ciphertext. In general, any scheme with this property can not be CPA-secure, can you figure out why?

On the other hand, PRF+OTP is not deterministic: it refreshes each encryption with a random value $r$. This key difference makes the scheme CPA-secure, the proof can be found in any basic book like Katz' Modern Cryptography (Thm 3.31 in the 2nd edition), but the basic idea is that if the value $r$ is not repeated in the oracle's queries, then the attacker get no information about the message being encrypted (so you have perfect secrecy in this case, just like in the OTP), and the probability that this does not occurre is small enough.