Maybe you are confused by the word "forced" which might sound a bit strong. I sort of copied it from Dub's statement. What I actually mean is that all three of those schemes have both: lovers and haters and the numbers for all schemes are around 50/50 percent of haters and lovers respectively, if all tus members vote. This makes intermediate as eligible of being in classic as the other two. And I don't know how this fails logically.
Let's be honest saying the one thing that was around longer has more rights is just a hell of a stupid argument that merely promotes ignorance, but fails to back up a statement. The 2nd main criteria a scheme should be judged by while picking for the classic league is its capability of providing a high level competitive gameplay. This means checking the scheme for things like: luck issues, balance issues, how much talent and time is needed to become top notch at it (I personally think the more the better), etc etc. Around those fundamental things you should build up your argument against it, not throwing in statements filled by fear of new things and losing. Sure, sure W:A is just a game to play and have fun, but let's face it you don't play classic league for fun only, you do it to feed your competitive demons. And you want to win the games with skill, not with luck. Once you really start to play inter you might see that there's less luck involved in inter than in at least 3 other schemes that already are in classic league. And I'm sorry I just don't see how "I don't play it, becasue I might lose." makes a valid argument.
The first main critaria is the popularity of the scheme btw. This poll says exactly 50/50 and it's almost a perfect number, because, and I repeat myself again, if seperate polls were created for every single scheme, then all of them would wind up around 50/50 with slight deviations to one or another side depending on the scheme.
Furthermore I want to seize the opportunity and advertise my intermediate cup.

Sign ups are already open
https://www.tus-wa.com/cups/cup-363/