Laying down a hard line at the start off negotiations is not "dictating" anything. It's your way of ensuring a good final outcome for yourself. The EU will not anywhere near completely achieve the things you say they are "dictating." Dictators tend to get the lot. Way back in the good times when unions were allowed to do their job of negotiating pay for their members, we would ask for twelve per cent, threaten all sorts, get round the table, end up with four per cent and everyone went away, not deliriously happy maybe, but clutching a settlement until next time. That's how it works. We call it "negotiation." We don't pay negotiators to give in and fold up at the first hurdle. The EU is following its guidelines, as I've shown. They've taken a hard line, true. They have to. But so are we taking a hard line. We want them to breach their guidelines and put everything on the table at once. That would be extremely foolish. We offered next to nothing in the overall scheme of things and it took us months even to do that. The EU wants to show that no-one should contemplate leaving lightly. Pour encourager les autres. To show that you don't get decades of benefits then blithely walk out leaving the rest in deep doodah. By so doing they are acting in the interests of the EU. Our negotiators are living in mortal fear of being seen to be weak by Tory hawks and the Farrago set. It's paralysing them. They are acting in the interests of their party, not of this country. In so doing they are holding things up and they are going to get a worse deal. The EU bigwigs are actually being quite nice to us in public. They can see that leaving the path open is in everyone's interests. In private they must be scratching their heads wondering how this country can have sent such a shower of incompetents to "negotiate."
So, setting strict targets at the outset is good negotiating practice if done by the EU, but folding to outside pressure if done by UK.
That seems to show that your support is for the EU rather than the UK.

To show that you don't get decades of benefits then blithely walk out leaving the rest in deep doodah.
More a case of having been a net contributor for decades. If we'd been a net recipient of the bounties of the EU we would probably want to stay in, and the EU would probably be more prepared to let us go.
They don't want us to stay in because they love the British. It's our contributions they want, hence the extortionate divorce bill which they are trying to push through.