Again, who is going to pay him that?
The Clippers can offer $10M, they are going to be paying Tax anyway, so they probably are not all that worried about paying a little more if they believe Batum is an important enough player. There will be a lot of teams that can offer the tax payer MLE (including the Celtics) at about $6.4M but teams in that situation cannot offer any more than that and since they are already paying the tax, they can't do a sign and trade without sending out a lot of salary.
It sounds to me like the Clippers could probably get him for say $7.5M. That beats all of the tax paying teams and teams that have cap space or who can offer the non-taxpayer MLE, probably are not looking to spend $10M on a player like Batum.
I don't know what level of interest the Clippers have but someone is sure trying to make it seem like they do. It could be just his agent trying to set a market price for him. If I was Batum, and wanted to get out of LA, I would just shop myself around at the tax payer MLE ($6.4M). Then he could probably pick his team.