You can't say the rules should same apply to all forum users, although I will not support plagiarism but the moderator's gentle attitude to forum contributors is highly expected. Losing one useful contributor to a forum with 1 error is not worth the hundreds of spammers there are.
This is one way I've been looking at this case. I feel for the user, really. Looking at the accounts rise and what job its been doing as per forum contribution, I'm sure there would have been more good from this user in the near future. It was out rightly wrong to have plagiarised and trying to cite an accused post for plagiarism seemed some worth fishy but, its just a position the pressure of loosing an account could create. You try to think fast and then thought wrong.
I really wish to see the likes of Pokapoka124 in the forum once more. The forums greater good is what's of the essence plus, we all have to do do our best in maintaining forum decorum. I'm sure the user must have learnt a lesson of this. Mercy please!