A grumpy exchange with a green politician

Grumpy on my part, that is - Becca is never less than diplomatic.
An introduction: in 2008 Lambeth Council steamrollered through a proposal for the resolution of traffic problems at an awkward junction that entailed destruction of over 1000 sq m of one of the most loved and well-used parks in the Borough. The Friends of Brockwell Park resisted it, and I supported them, but all seemed lost. Until I got a message concerning Lambeth's refusal properly to consider an alternative scheme, that not only saved 400 plus sq m of park, but claimed to improve several road safety issues. I got a little heated, and sent the following message, with others. This one, though, was to a Green Party councillor (the only 'green' in the council chamber). I've posted it here because the exchange of emails (each of which is entered as a 'comment' below) broadens out the debate: