The EU will negotiate when the UK invokes A50
Most countries in the EU are willing to agree this point in advance of any negotiations. Unfortunately one or two are not.
It is only the UK who is sending out "prepare to depart" letters to frighten E27 expats
We could try being accurate here. Some EU citizens living in the UK are worried about the situation and are applying for permanent residence. If their paperwork is not correct they receive a letter saying they should prepare to leave. This has long been the process. The letter is bureaucratic, causes unnecessary worry and needs to change. But it is not new and it is not the case that EU citizens are being told generally that they need to prepare to leave.
they could have made their own conditional amendment: to say they would allow E27 expats to stay, provided UK expats could stay
This bill will become an act of parliament. You don't put a negotiating position into an act of parliament. The government has stated repeatedly that securing the status of EU citizens in the UK and UK citizens in the EU will be a priority as soon as negotiations begin. I see no reason to disbelieve them, especially since they have publicly made the offer to the rest of the EU.
I'm a Uk expat and there just isn't public pressure to lower immigration from other EU countries, or even from the Uk
Why are ECREU (Expat Citizens Rights in EU) worried then? They talk about "the fear and worry that so many British citizens in the EU have". Are they wrong?
The UK govt is NOT protecting UK expats by being tough to E27 expats
So why aren't the remaining EU countries rushing to guarantee the right of UK expats to remain? There is nothing preventing them from doing so. Indeed, the government specifically offered to agree this immediately.