its good let emotions cool in cases like this. and to give CS time to fully investigate. these situations are more morally ambiguous than you are allowing for right now.
for example, this dude may have heard of this from several other folks who are all doing it. they may assume a significant portion of the community is already doing it, which makes not doing it, a competitive disadvantage. it really matters a lot how widespread an activity is, in making these kinds of calls.
for a historical HD example, for a long time, game admins would not confirm or deny pulldowns existed for d2/d3. a small %, i mean significantly less than 5%, of users were using them, and basically it made the better ones among those users non-competitive with the 95%+ of the community, it was an un-bridgeable gap.
this was OK - it was intentional behavior put in by the original creator. but how did those users know it was ok? if they stopped to think about it, which probably never happened, it might have been a pretty reasonable gray area to consider.
then later, due largely to some outrage, the game creator came out and said point blank 'we removed pulldowns from the game'. but that wasn't true. a user found a way to keep doing them, and slowly some others caught on. normally, if a game creator says 'X is impossible', and a well-informed user finds that is not true, and exploits it to great effect - which happened in HD - i would consider that on the wrong side of the line. reporting it would be a minimum necessity, and if the game staff was like, that's fine, or ignored it, then maybe you go ahead. but at least give them a chance to fix it. its different if you already know 50 other people are doing it, then you are really putting yourself at a disadvantage not to use it.
anyway, in real HD, the game creator was super unclear about what was intentional or not, the impression i got later was, he knew pulldowns were still in the game, when he told us they weren't, and he did it 'for the mystery'. this creates near-impossible moral quandries for the user base, and in my opinion, its the original game creator who was unambiguously wrong in the above, completely true story. nobody knows 100% of the story, because of that intentional ambiguity, but frankly it was complete bullshit almost any way you can spin it.
to be unambiguous cheating, in these sort of circumstances, you need some real factors against that person. like if someone hacked into the WIS servers and changed the game outcomes, its not against fair play guidelines, but its probably against terms of use of the site and regardless, is unambiguously cheating. if you create a tool to expoit a glitch in the game, like aim bots in shooters and those sorts of things, the tooling creator is almost surely unambiguously cheating. its different to be the 10,000th guy to download the aimbot, but by then the site staff usually clearly call that cheating and perma-ban that guy anyway. the original creator of the hack / exploit / whatever you want to call it, may not have actually violated written rules, but users of that level of competency also have to have a higher bar applied to them. they should know better. and nobody reads the terms of use anyway. sometimes you have to call a spade a spade.
it sounds like the user here didn't use external tooling, or use security vulnerabilities in HD to reach their ends. its unclear how many users are doing this, i've wondered a bunch of times how people had so many AP on certain players early, where i'm very low with 20AP and the guy in the lead is on other people. this guy who you caught may well be the only guy, or may well be the 100th guy, who heard about it from 3 different friends before he started himself. its super unclear based on the info provided.. and it is VERY hard for site staff to perfectly navigate these issues, especially when paying customers are involved. some allowance for the complexity of these issues is really called for, from the user base, from us.