If we hit the hottest temperatures since records began then I’d say it is pretty newsworthy.
In terms of personal responsibility, I get that but then others do have to think about collective responsibility too. Services always come under pressure in situations like this, be it from increased admissions from people with heatstroke, idiots going swimming where they shouldn’t, fire services stretched due to people having bbqs on ground that’s just one big tinder. All of them then have an impact on shifting resources to what could have been unnecessary, from dealing with unavoidable emergencies.
If you’re sensible and capable of applying common sense, brilliant. Some of the messaging and the fear aspect of it in particular isn’t for you, ignore it. If it stops even a few idiots and means that services are there for if you do have an emergency yourself, then it’s worth it.