I think the point the previous poster is trying to make is that:
> This license restricts how a product can be endorsed/promoted as per the clause.
...is technically not true for licenses, because they do not _restrict_ usage, rather they _permit_ usage. The usage is, by default, always restricted by automatic copyright and authorship laws, so any license (including the GPL) is not a restriction but a permission, since it has _granted_ permissions that were implicitly not there.
So if you change your license in a way where it appears more restrictions have been added, but those restrictions were already implicit because they were not even covered or taken into account in your original license, no new restrictions were added, your "grant" was just made easier to understand.
> This license restricts how a product can be endorsed/promoted as per the clause.
...is technically not true for licenses, because they do not _restrict_ usage, rather they _permit_ usage. The usage is, by default, always restricted by automatic copyright and authorship laws, so any license (including the GPL) is not a restriction but a permission, since it has _granted_ permissions that were implicitly not there.
So if you change your license in a way where it appears more restrictions have been added, but those restrictions were already implicit because they were not even covered or taken into account in your original license, no new restrictions were added, your "grant" was just made easier to understand.