Why MDF so Bad???

Hi everyone,
I've been reading left and right about how bad MDF seems to be for equipement racks. Everyone seems to agree that MDF shelves will color the music badly. The only thing I wonder is why do many speaker companies use MDF in their speakers?

Also, does MDF sound bad in every thickness? Did someone try to use 1 inch thick MDF shelves?

I'm very curious about MDF so I'm getting a woodsmith to build a 5 shelf equipement rack made of 1 inch thick MDF (only 1 inch thick MDF will be used for the whole unit). The shelves will be fixed to the frame. The whole rack will be assembled using high strength glue only. No nails nor screws will be used. The rack will be veneered with 1/28" thick mahogany wood (no paper backing)... Also, the back of the rack will be reinforced by MDF braces... The overall rack will be as rigid as possible.

One more thing, the rack will sit on the same kind of spike Verity Audio uses on their Parsifal encores (I guess I want the rack construction to be as close to a speaker cabinet as possible)...

I'm getting this rack made as an experiment, not as my definitive rack.

Any opinions as to what I should expect from this rack (sonic qualities)?

I was also thinking to use some sound absorbing material under each shelves and on the inside of the sidewalls to try lowering sound reflection (am I off the track here?)...

One last question, any thoughts as to how I could improve this rack (please don't recommend to throw the rack out the window and get a brand name rack)?

If anyone is interested, I will be able to post some pics when the rack is ready...

Your input is greatly appreciated.

Thanks ahead