As I said, only the dividend goes to Glazers (and other shareholders), the other money remains in the club and is reinvested, be it on the team, academy, stadium, commercial deals etc.
To be totally fair, some money goes into interest payments (which would have gone in taxes) and a little bit on taxes (would have been more if it wasn't for the interest payments). Regardless all the money combined for dividend, interest payments and taxes is I believe less than 50m pounds, or less than 10% of the money we generate. The other 90%+ is reinvested.
Anyway, even that 10% that goes out is totally normal. Everyone pays taxes bar Catholic Church, and owners of every business get some money from that business, otherwise they wouldn't own it in the first place. Regardless, the money which goes out is not significant (circa 20m) compared to the money which is reinvested (500m+).