There is a connection manager (that kills connections when they go over a limit), and I think there is a connection rate limiter that limits how many connections are initiated. Some connections are protected (those manually initiated, or those that are being used to transfer some data etc).

It is however true heavier IPFS usage results in more resources used, or slower experience in general. It is also true that the connection manager could be improved to be more expedient in handling spikes.