I've not had a takeaway for years because of Covid, but I wouldn't think twice about ordering one in this heat otherwise - it makes a lot of sense to order from takeaways to avoid generating extra heat by cooking at home. It will also help reduce energy and water consumption, the infrastructure being under great strain at the moment.
A lot of takeaways have closed because of the heat, if they choose to open then that's their lookout. A lot of delivery drivers are freelance - they have the choice of whether to work, and who am I to dictate they should not be allowed to drive in an air-conditioned car to take orders to customers?
If you decide it's wrong for people to work in takeaways or as delivery drivers in this heat, where do you draw the line? A lot of work is non-essential in the grand scheme of things, certainly there's nothing I had to do today that couldn't have been put off until the weather cools. But I need to earn money, so I put up with travelling on a scorchingly hot bus to sit in a boiling office.