Uh, isn't that exactly what you'd want out of a political party? I wouldn't vote for them because I disagree with a few of their points, but if you think all of their policies are good and you trust them to uphold them, then go vote for them?
> know what they can actually achieve and promise that
Show me a single party that actually keeps their (concrete) promises and I'll show you a flying pig.
In any case, you're somehow confusing a list of "key issues" with a list of actual promises. A 30-hour workweek being a key issue, doesn't mean that the party promises they'll achieve that the next term, even if they magically would get 100% of the votes. It means it's a long term goal that they believe in and are working towards. Isn't that obvious to anyone with even a passing issue in politics?