That's like saying a £5 pair of headphones is "audiophile grade" for the price. While it doesn't have a strict definition it definitely doesn't mean good for the price.
No it's not. You're misconstruing my statement to make a cheap semantic point. An "audiophile" grade product is the product that best reproduces sound for that class of device. If we were talking about headphones, then a $5 or £5 headphone wouldn't be audiophile grade because the components to accurately reproduce the audio can't even be found for that price, much less the whole package. In this case, we're talking about a class of product - wireless smart speakers. If there were enough of them on the market, we may be able to separate these into budget, consumer, and professional. The point is that the HomePod offers the best sound reproduction in its class.