It's less that it's a claim by Huawei and more that the claims haven't been verified independently. Competitive benchmarking has a long history of results which are hard to reproduce and comparisons which “accidentally” left the competing product in an unusual state, so it's prudent to distrust them until they can be verified independently.
I am not sure what industry you are in but if you go read press releases from the likes of most of the networking companies you see all the time “bob networking unveils the biggest flubar...” or the like as standard practice. Heck I have had to edit some of these for technical correctness before the marketing team puts their foot in it..
And in case anyone is wondering why they do that: press releases are intended to be used in an article verbatim. Headline and all. Press releases are written from third person perspective because that's how a reporter would write it.
And if you go on Google and search some text from a press release, you'll find tons of articles using the headline and body completely verbatim like it's their own article. This is intentional.
News outlets print them verbatim, and it's traditional to read like that (as opposed to e.g. "we released a CPU" which on a news outlet it would make it seem like the outlet's team released the CPU").
