their date of joining doesn't matter if they are genuinely selling.
Not to be a downer here, but actually, it does. This is an electronics engineering forum that happens to have a buy/sell/wanted section rather than a forum for selling merchandise that dabbles in electronics. Typically, those who come here only to sell items attract the unwholesome attention of the moderators and are typically banned.
If new users should not post anything for sale, how are people going to sell their stuffs?
By selling them on appropriate websites for selling such stuff. Ideally, new users should be a member for a while, asking questions and/or contributing to other forums here. Then, everyone here will see that there is a real interest in electronics, not someone just looking for another outlet to flog stuff,which will not go over or end well.
Old Printer and Blueskull's views are not preposterous in the least. Everyone here on the EEVBlog frowns on shills and floggers, especially the moderators. By the way, ridiculing possible customers for their views whilst trying to flog merchandise to them? That's preposterous. Methinks that if you continue on your path here, you will be reported and then banned. Just offering some advice. Do with it as you will as long as you are willing to accept the consequences for your actions.