Why shouldnt they be allowed to make a cap at 10M?
For baby 10M+1 are they going to tell a Swiss woman that she can’t have a baby?
In any case, this is definitely not conformant to the treaty that the Swiss have with the EU around rights of free movement.
This wouldn't happen because it's not actually a population control measure, it's an immigration control measure - when the population gets above 9.5M, Switzerland would start shutting down immigration/asylum. There's nothing in the initiative that would set controls on births by Swiss citizens. (and it would be unlikely to be needed since Switzerland is facing the same low birth rate of other western countries)
Organic population growth doesn’t have to be criminalized or authoritarian-controlled like China tried.
It's primarily an attempt to control immigration.
At 9.5M, the government has to start limiting the issuance of residence permits and start renegotiating international commitments that drive population growth.
At 10M, the government has to terminate the free movement agreement with the EU.
The right-leaning parties bring up something like this every few years. They always get shot down.
The only way you could argue an initiative is "against the Swiss constitution" in my opinion would be if it runs afoul of the rules: https://www.fedlex.admin.ch/eli/cc/1999/404/en#tit_4/chap_2
Unless you want to argue that this violates the mandatory provisions of international law, I don't think you have an argument. The text of the amendment specifically clarifies that any of the actions it mandates on parliament have to adhere to the mandatory provisions of international law, so I don't think that's an avenue you can pursue.
However, they do have Art. 7 (human dignity) and Art. 8 (equality before law), which applies not only to Swiss citizens, but to all humans. I don't know about you, but I would think that excluding refugees who need help because we already have 10M people in the country would be against their human dignity.
But, it does seem like a terrible place to live. I fear for the immigrants who form the basis of the economy.
When people talk about immigrants in this context, I don't think they mean people from the US, but lower socioeconomic asylum-seekers and refugees etc. from the middle-east.
It definitely seems their economy was built on European labor, which I believe the vast majority of European countries were.
[1]: https://en.wikipedia.org/wiki/Demographics_of_Switzerland#Pe...
They really don't like asylum seekers either though. Several of their arguments reference asylum seekers specifically: https://nachhaltigkeitsinitiative.ch/argumente/