Lacewing flies are not harmful to humans or pets.
And instead lacewing flies are actually considered to be beneficial, especially for gardens and garden environments.
Lacewing flies are known to prey on various garden pests, which include whiteflies and aphids.
And although it's possible that lacewing larvae can ocassionaly bite humans and cause minor skin irritation they are not a great threat to humans and pets and are more helpful and beneficial than they are harmful.
The lacewing larvae and lacewings are voracious predators and eat a wide range of soft bodied insects including whiteflies, mites and aphids.
And the lacewings are a very effective natural control agent for many different garden pests, and help to reduce the need for using chemical pesticides.
Lacewings do not directly harm plants either as their main food source is eating other insects and the lacewings also do not damage plant tissue.
Lacewing larvae do possess mandibles which can be used for defense or to feed on other insects and in rare cases they have bitten humans but it's not often.
And if a lacewing larvae does bite you it's often just a minor irritation and not a serious issue.