In abandoning socialism, even social democracy, you have cut yourselves adrift from your heritage, values and language. As parliamentary politics lurches further right into the darkness of neoliberalism you find have no vocabulary and no ideals of your own. The Tories define the linguistic, philosophical and political ground on which you will fight or, more accurately, from which you will retreat. Your words, your priorities and even your policies are borrowed from them and reused on their terms.
Surely, at some point even you have got to decide it's time to fight, that you can shift no further to the right, that it's better to be risk defeat with integrity than to risk victory with your opponent's policies. When will that be? Where is that point at which you decide you can demean yourselves no further? What aspect of the rubble that used to be our society will induce you to rally?
Why do you found a political party? Is it simply to get power? No, if that was the reason you'd join an existing party to use as a platform. At best you'd try to influence it 'from within'.
No, you found a political party to campaign and argue for ideals in which you believe that aren't being represented by existing parties. The idea that public opinion is unchanging and unchangeable, and political parties have to manoeuvre round it, is bizarre. It's worth noting that the Tories certainly don't believe this - but it suits them that so much of Labour does.