To bring it to the point. The reference to "overcoming capitalism" comes from a now rather old political programme setting out a series of mostly vague objectives. In practice, a party's manifesto is all but irrelevant in Swiss politics because political decision making is not based around a party coming into power with the intention of implementing a manifesto; or even with the intention of using it to negotiate a governing programme with potential coalition partners.
Legislation in Switzerland is initiated largely from parliamentarians themselves; albeit with some input or projects being initiated by the Federal Council. Meaning that the executive actually has very little influence over either the parliamentary agenda or over how parties vote in legislation. Instead, almost everything is centred around negotiating and parties bringing their own perspectives in order to try and find a project that will eventually be able to obtain a parliamentary majority (and eventually a majority at referendum, although actually most legislation does not wind up going to referendum ever).
Now, in practice, the PS are unusually radical for a SocDem party. That is the case rhetorically, as well in the way that they behave in parliament and in the positions that they take in referendums. For example they supported a campaign to tax capital gains not just as income, but as 150% of income; and are currently collecting signatures on things like a 50% inheritance tax and - rather more far fetched - a 100% wealth tax over 100 million CHF. They are also, in contrast to other Soc Dem parties, more or less irreproachable on issues like LGBT, migrants and refugees rights and express nothing but wholehearted support for all of them; and unlike other Soc Dem parties, they have viscerally opposed the liberalisations of recent decades. Their success in doing so is a large part of why Switzerland is not currently experiencing a cost of living crisis that is at all comparable to the rest of the continent.
But, the point is, the way the Swiss political system works is essentially that is encourages this sort of radical posturing for essentially two reasons.
The first is that you enter the scene with a radical position in order to come out with one that basically works for you. The PS need to make it seem as if there a heavy weight in favour of very radical left wing measures in order to counteract the right wing majority and eventually bring round enough centririst (Green Liberal or Christian Democrat) MPs to implement a somewhat acceptable solution.
The second is, in a country with a more-or-less permanent governing coalition, "antisystem" posturing including on the part of the governing parties is more or less a prerequisite in order to both motivate your support and to break the most fundemental and overriding force in Swiss politics - which is inertia.
Or more to the point, as far as that "overcoming capitalism" line goes. It's not really relevant, it doesn't bear on the parliamentary agenda, or what the PS's members of parliament vote on or propose, or the positions on individual issues that they take. What is does, or did do, is function as a nudge and wink to people on the left that the PS shares their values and that they are the best force for achieving those.
Thank you for the explanation, I appreciate it!.
Based on that, I would be a supporter of the Social Democrats
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