Well yes if you are literally incapable of pairing good mons with chansey its F tier, but thats not how mons works.
Chansey is able to put up an A tier preformance vs other mons because it is good and not outclassed (in fact it is the outclasser.)
Saying "Its only good if you pair it with good mons!" doesnt help your argument. A VR is a snapshot based on how good the top 16 rby circuit players think they are, which then tells us ~how often it should be used.
If you struggle to understand that some teams are bad with a mon or that some mons are good on certain structures thats fine and dandy but we have samples with explanations for a reason.
If you really wanna die on this hikl think of it this way: A mon on the VR is ranked based on the value it would provide on a good team over other pokemon and how good those teams are due to having it.
If I may a hypothetical to you though.
What VR ranking do you consider each of these? Rock, Paper, Scissors?
Let's say Two players are playing Rock, Paper, Scissors against each other on a online platform.
And you have to rate the viability ranking of each of them.
But you also know the usage rate data for the month is showing this:
Rock 39%
Paper 27%
Scissors 34%
That makes rock temporarily S-Tier, even if they are all the same tier otherwise. Yes or no?
Example:
Rock is S-Tier
Paper is B- Tier
Scissors is F-Tier
For the example VR list.
And this is what I'm trying to say happened to cloyster, that because people are essentially using rock 39% of the time, it then makes cloyster S-Tier because of why everyone is using this clump of things(Tauros,Snorlax,Chansey,Exeggutor) that cloyster plays well vs this. This is like having my opp use rock 39% so I turn have to use rock based off of why they also use paper lower than scissors. So I have to use cloyster to overcompensate for the clump of 4. because I see rock being used too much.
Here is my example again:
Rock 39%
Paper 27%
Scissors 34%
See how others using rock too much makes it mathematical that you have to also use rock too?
Its not that rock is intrinsically S-Tier it's that other people using exact things creates the viability ranking.
Edit: although in pokemon some things are intrinsically S-Tier because of like how Aces in poker are intrinsic to being the best. There are some mons that are intrinsic, like Mewtwo and Mew, but they were banned for being intrinsic to winning. Everything else is considered intrinsic to being balanced enough that each mon isn't intrinsic to winning. Therefore S-Tier is considered something less than what is considered to be intrinsic to winning otherwise it would be Uber, Uber as a tier ranking would be above S-Tier.
So my point being that if everything in the game is considered to being balanced enough that they aren't intrinsic to winning, why would Tauros find it's usage rate at what it is? Why would Snorlax find it's usage rate at what it is?
What about Chansey or exeggutor? They aren't intrinsic to winning so why play them 9 to 10 out of 10 times?
If everyone is...that makes the clump of 4 being either all or some of them are then Uber and they aren't being accurately classified as such or why have that clump being used at the usage rates they are? I think the game itself has so many things to expand to because of stuff like this.
Things that I think could happen?
Tauros is Uber? No.
Snorlax is Uber? No.
Chansey is Uber? Maybe.
Exeggutor is Uber? No.
Chansey has more characteristics to being similar to the Uber things than the others do.
But I'm getting off the original focal point that the main message is that if those 4 things are all used at rates above 70% than I'll net 2-3 or 4 of them often every single game, and I'll slowly bring cloyster to the victory that it deserves!!!!