Still I will strongly suggest, delete your post history those are spam. Then try to make or perticipate on constructive discussion. Perhaps some one will merited you.
But how? They could be deleting their whole post history (most of the times 200300 posts, and I have seen quite a few Jr. Members with staggering 1200+ posts, before the 1 Merit update!).
That's what many are doing. Just to plagiarize a post and then, after obtaining their merit, deleting it. So, if we don' t have their previous activity to judge the natural behaviour, how are we going to suspect of the new threads they make? Do not forget that many people are committing plagiarism from translations, meaning, using an article in their own language as a source and then google to make a translation. This is hard to detect, so the context seems pretty important to me, though.
And vice versa. I have seen posts in the past few weeks on local board suggesting that the local board members should 'help' each other by giving merits as we are all 'brothers' instead of giving them to 'strangers.' Then they post a translation (from English to their mother language) of an article/guide (Google Translate evidently) and actually manage to get a merit or two. There are others who put some effort in the translation, which is welcome to help those whose English is weak.