My thinking on that is simply that May didn't need to call the election for Brexit. She has a majority, Labour have made it clear they won't block her and she said to Sturgeon that the country does not need the uncertainty of another vote (in the context of IndyRef2 obviously).

She has simply seen this as an opportunity to exploit a weak opposition trailing in the polls and give herself five years with a bigger majority to push through her real agenda. We already know from her time as Home Secretary that she is intent on reducing rights and freedoms and giving greater powers to the security services. The Telegraph is now pushing the need to scrap clean energy policies in favour of cheap because that's what we need in post-Brexit Britain apparently. The NHS is dying on its feet as tjj's stark post shows all too clearly. To my mind this is simply opportunism, Brexit has presented the opportunity to redraw the balance and to legitimise many long-desired Tory policies on the basis of post-Brexit necessity.

Our ability to negotiate with EU27 will not be affected by the size of May's majority, but rather by the ineptness of Davies et al. The other issue lurking in the background is the ongoing investigations into Tory election fraud during GE2015, this represents an opportunity to bury that too.

[edited for typos]

In the absence of evidence or explanation as to how voting Tory can do anything but the reverse (as you rightly say), it must be more than self delusion, it has to be a deliberate ignoring of an inconvenient truth because there is some advantage to themselves (not sure what though) in voting for a party that demonstrably fails every time it is in power to reduce the gap between rich and poor and in fact goes out of its way increase that gap.