What type of fallacy is this? (Featuring Bertrand Russell)

Someone on Quora asked the question: "Why was Bertrand Russell so critical of Nietzsche?". One of the responses especially stood out to me as it was written by a professor of law with a BA in philosophy. You would expect someone with those credentials to have a well thought-out answer; however, it is mostly a collection of personal attacks against Bertrand. If you're interested, the full response can be found here. 

For this question, I am specifically concerned with the following excerpt:

"Unfortunately, for all his literary fluency, Bertie was a failed philosopher and the most he accomplished as a mathematician is providing us with a formalism which requires at least 450 pages of close notation before reaching '2 + 2 = 4'. Extraordinary rigour in the service of triviality is NOT what philosophy is about."

Here, the arguer is trying to frame Bertrand's work in a way that makes it seem unduly trivial. It strikes me as an obvious fallacy, but I can't put my finger on it. Perhaps it's just an ad hominem, but it also reminds me of those arguments that try to reduce a complex phenomenon into 'nothing more' than an interaction of its parts. For example: "Music is nothing special. It's just a bunch of soundwaves entering the eardrums and being interpreted by the brain." 

What does the Logically Fallacious community think? I'm looking forward to your replies.

Thanks!

Sounds to me like a clever ad hominem attack, along with an unsupported claim. As you stated, there are those who make arguments that try to reduce a complex phenomenon into 'nothing more' than an interaction of its parts. 

"Unfortunately, for all his literary fluency, Bertie was a failed philosopher and the most he accomplished as a mathematician is providing us with a formalism which requires at least 450 pages of close notation before reaching '2 + 2 = 4'. Extraordinary rigour in the service of triviality is NOT what philosophy is about."

Unsupported claim and opinion I guess - where's the evidence he pretentiously pontificated about how 2 + 2 = 4? Without that, it's an unverified (but testable) positive statement.

The implicit argument could be that Russell's work is trivial, but this would then be a case of the premise (writing 450 pages to reach the conclusion 2 + 2 = 4) being true or false.

It  would  be fallacious if it tried to dismiss him out of hand entirely.

I agree that there's no fallacy here.  However unfair it is effectively snarky criticism.