I think (and will be corrected if wrong) that the sentence should be interpreted as

When xIE=0, Interrupts for lower-privilege modes, w<x are always globally disabled regardless of the setting of any global wIE bit for the lower-privilege mode."

No, that is not what it says or means. Interrupts for lower-privilege modes are always globally disabled regardless of xIE (i.e. the bit in mstatus for the current privilege mode e.g. mstatus.mie when in M-mode).