@James3078 While I agree that guests should not be shown listings that don't conform to the filters they have entered, guests also need to read through all listing information before submitting a booking request.
That you were declined means not only were you shown a listing which in fact did not accept children, you obviously didn't bother to read any of the host's house rules, or you would have seen that it said unsuitable for children, as well as seeing his other house rules.
It is a guest's responsibility to read all the info provided, including house rules, the cancellation policy for the listing, and any requiremments the host has for approving a booking.
Many of the issues that arise between hosts and guests are due to guests just looking at the photos and price and glossing over the listing wording, if they even bother to read it at all.