Well yes, it is an uncleanness issue moreso, it is still a sexual sin as well because it pertains to the sexual anatomical parts as well as the fluids and an sexual act, though the sex acts don't neccessarily always have to be part of it (ie: wet dreams for males, for females the period) are all also sexual uncleanneses and more minor sexual sins that are regulated and have biblical prescriptions for maintaining cleanliness. Though yes, because the issue is more to do with cleanliness and really is on an individual level whereas most the more grave sexual sins involve multiple people, the prescription in this case for this sin is water and abstinence and repentance.. Compare to the more serious sexual sins like cheating or whoredom in which case the prescriptions is to put away the blood of the wicked from the land. Indeed the uncleanliness factor as well as the sexual factors are all linked and thus Adulteries; pollutions. This is the whole basis of the concept of the adulteries, and there are many forms of the adulteries and various ways to expiate them. If you've studied the Bible close to as much as I have then you would know easily what adulteries are, all their diferent forms and scenarios, and the links to cleanliness and uncleanliness. Large portions of Law are devoted to thoroughly outlining this. And we haven't really even touched the prophets and spiritual dimensions to this yet, which frankly are much more severe than the Law when you start weighing an eternity into the hellfire into consideration and are found the New Testament, not the Old.