Ah, the ever popular "hey, can you re-create Einstein's theory of relativity for me right now? No? I guess physics must be fake, then" argument, popular with bad-faith conversationalists of all stripes.
Links from the BBC article you appear to have missed:
"Antisemitism on Twitter Before and After Elon Musk’s Acquisition"[1]
"The Musk Bump: Quantifying the rise in hate speech under Elon Musk"[2]
Additional studies:
"Hate Speech Spikes on Twitter After Elon Musk Acquires the Platform" [3]
"Auditing Elon Musk’s Impact on Hate Speech and Bots" [4]