You're not even using the right definition, you're using that of a check, which is different. Rillaboom being able to switch in once counts as a counter, because it can beat out / force out barraskewda 100% of the time.
"Getting in for free" doesn't exist in this case, unless you're counting switching in with an HDB water immunity. Being a counter doesn't necessitate being able to "come in for free" because that's an unrealistic expectation that pretty much no Pokemon can do. Skarm doesn't "Come in for free" on Iron Boulder, even though it's generally considered a counter, it can take 30% from Mighty Cleave, Plus stealth rocks damage, and is forced to roost.
"Dondozo should never be used to say" why not, it's what it does, it beats the mon, i was providing pokemon that beat Barraskewda.
Sinistcha being fringe doesn't make it not a counter, I listed a ton of way more splashable ones, nitpicking the least usable one because a counter "needs to be splashable" just isn't a real argument.
Okay, I accidently used the wrong definiton, my bad. I'll link a photo to what smogon defines as a check and counter.
Note it says "wins every time, even under the worst case scenarios", which in this case, is if cc is clicked, which can happen.
Only dragonite, dondozo and hydrapple have reliable recovery, so every other mon has to be careful.
The reason why I said dondozo shouldn't be used to say a mon is counterable is because it is the ultimate phys.defensive wall, if you are having to use it to counter a mon, then that means it has extremely limited counterplay, which is a sign of its unhealthiness. I won't state that again if you want me to, but I think we shouldn't have to name dondozo as a counter to phys.attacking mons because it is already known it can counter most physical mons.
Sinistcha is fringe, doesn't make it less of a counter, but it means people are not using it a lot. If it was simply a case of it is better than people thought, sure, you could say it is a great counter. But if you have to force yourself to use it to counter barra, that isn't healthy.
I won't keep discussing this as Finch stated it would be his last post, and I am kinda getting annoyed with the back and forth that keeps getting repeated, but I haven't seen any reason to change my opinion. If you think barra is balanced, cool, but I disagree with you. The counterplay is vunerable to barra's coverage and while that may mean it gets weaker, it is worth it to take out the counter to barra, which means long-term the rain team can take advantage of that.