Sometimes there is a malicious intent.
However, many times there isn’t. For example, if I like the username yitayningwut and I already use it on a few different sites, and I come here and see someone already has it (because it’s such a common and sought after user name, right?) then I’ll call myself yitayningwat or yitayningwut1 etc. The example you have given is a name which most probably lots of people think of, hence the various versions of it.