Why so many vehicles?

It really is ridiculous, 1 ambulance and the air ambulance if needed and 1 Police car should have been enough.

From the news report, the man was found alone in the house with a number of dogs. Presumably somebody heard a commotion, rang 999 and as they didn’t know what they would be dealing with, a full emergency response team was sent. That seems reasonable to me in those circumstances.

Presumably the vehicles that weren't needed were redeployed ASAP.

If they hadn't sent so many and the incident had turned out to be more serious people would be criticising them for not taking the situation seriously enough.

No win situation.

Why is it ridiculous? As Casdon and Septimia noted, this was a serious situation, with unclear information on what the response teams would find on arrival.
It’s so undermining of our first responders to leap to criticise.

YABU. Perhaps the man had a family and there were fears that there were more injured people inside. What a sad story, though.

You have different skill sets, RRVs often have critical care paramedics on them, it would have been a hugely chaotic scene with very distressed family members who would potentially need medical attention. One paramedic is not enough to do a complicated resus such as this. HEMS teams carry blood which may have been needed.
Possibly better to leave the decision to those who have the expertise needed rather than to criticise without knowledge.

Under those circumstances, it makes sense

because they were trying to save his life.
what is your objection ?