A foul (or the vast majority of those type of decisions) are always going to be subjective. Just because the VAR officials agree with the ref on the pitch doesnt make them wrong or more importantly the process has failed......just cause i think it was a red card (and others think that) doesnt mean we are correct..
On some days it will be given - on others not.....depending upon the official, depending on possibly what the payer has commited foul wise on the pitch before (at least for the on field ref) - VAR just happened to agree witht he ref on this point that it wasnt a sending off...I think they were wrong and it was a sending off
Human beings will have differing views of the exact same incident....a foul/sending off isnt a black and white decision....offside is closer to this (though the rules are abit fucked up with what body part etc)