Vaporeon is a Lapras counter?

Ice takes normal damage from Water, but Water resists Water... so I am not sure why it says so.

Vaporeon is not a Lapras counter but it is not the worst option to attack a Lapras (i.e. there are a lot more worse pokemon to put up against a Lapras). Their attacks are both ineffective against each other since both have water typing (Lapras being water/ice).

I often use a Hydroblast Vaperon vs Lapras.

Longer fight because both of us are not doing "not effective" damage. And while the moves are similiar in Power Level. It boils down to the fact that I Dodge and the Computer doesnt. So ties easily go to the Vaperon.

((Incidently though the opposite works, you can take down a Vaperon with a Blizzard Lapras just as well))

We formally define a counter as an attacker that beats a defender without having to dodge at all.

Vaporeon beats Lapras without Vaporeon having to dodge at all. Therefore, Vaporeon is a counter.