Valid point. Some discussion necessary, here.
It's not a feat in and of itself, but Kraven has speed-feats on top of this and has the clear presentation of someone who has jacked themselves up past human possibility, into the superhuman range, through the use of his various potions. This is also noted in his fights - Kaine, Peter's clone, comments on Kraven's speed while fighting him (as an example). And the whole 'potions make him stronger, faster, tougher' ties into other feats, like the potions making him strong and tough enough to eat a full-on punch in the face from an enraged Peter Parker, spit blood, and grin; nothing more. If his speed is also enhanced to similar superhuman levels...he would clearly be able to at least try to keep up with Peter.
This is not the same sort of PIS where Peter whines about Logan's speed when fighting Wolverine; unlike Wolverine, Kraven is presented as being out-and-out superhuman. As Pendaran has noted, Kraven is a guy who doesn't have reams of comic book appearances; what we have for him is a few feats, some fights to try to gauge where he might stand, and his presentation. And in those fights, he consistently keeps up with Spider-man, Daredevil, and Tigra Edit: also Kaine, Peter's clone.
And what I've seen from Kraven is enough to make me say 'sure, keeping up with Spider-man may not be a feat, but it's not something that can be just dismissed as the usual speedster PIS, given Kraven is SUPPOSED to be superhuman. In this case, him kinda-managing to keep up in a fight with Peter is part of his presentation.' This isn't 'person with zero superspeed and no presentation for such keeps up with someone who has superspeed.' It's more similar to the character known as 'The Cat', who explicitly fights evenly with Shang Chi in his couple of appearances and is actually presented in the writing as his equal, and the Lizard, who is presented as being really, really fast and whose big 'speedfeat' is 'makes Peter sweat bullets and thank his Spider-Sense because the Lizard is so fast'.
Hopefully that clarifies.