The carers were apparently not being all that caring though, considering they just laughed when one of the people in their care hurt himself.
People are suggesting that if the children were being sufficiently supervised then there wouldn't have been a problem, but the adults were not being sufficiently supervised.
I've seen people on here being openly critical of helicopter parenting, which is effectively what is being suggested here as a solution to the problem of small children being scared by adults playing in both sections of the play park, because the OP does say that it is split into a toddler area and a section for children up to the age of 14 and these adults were using both areas. And an average 14 year old will not necessarily be the same size as an average 30 year old or even an 18 or 20 year old.
There is a big difference between a parent taking their child down the slide and an adult playing on the slide. And a toddler would perhaps be equally as scared by a running, shouting teen as a running shouting adult, which is why the carers at the very least should have ensured that they didn't use the toddler equipment or play in the toddler section.
There are a couple of threads on here right now, one about the OP's son not being allowed on a bus in his wheelchair because there were prams on board and another about a swimming club for children with SN that received a complaint because they use a shutter to make part of the changing rooms private and a woman thinking she couldn't reach her locker while they were there. In both those cases I think the bus driver and the complaining woman were very wrong but in this case the carers didn't seem to be doing anything to help anyone share the playground in a reasonable way and they were in the wrong not to do so.
I don't think adults with ld or sn should be hidden away, and I am currently seething at my friends new neighbour, who has pointedly ignored my friend for a few weeks before openly laughing at her when she went out one day on her mobility scooter and commenting that she should be forced to move into special accommodation so a normal family can have her house. My friend is 38 and has suffered a series of strokes which have left her unable to walk unaided. It makes me furious that someone can be so petty and vile to a woman she knows nothing about other than that she relies on a motorised scooter to maintain her independence.
But in this case, both parents and carers needed to take appropriate steps to ensure that the children and adults in their care were safe, happy and using the equipment and play area appropriately so that everyone could enjoy their time there and nobody had to leave.