Question On Floor Ruling

[Nalapoint1]

B&M MTT. Blinds are t2000/t4000.I am in the pot with both blinds. I am UTG +3.I have t20,000. SB t25,000. BB t500.
Checked to BB who goes all in for t500.I call the bet and the floor is called over for a ruling. The other players not in the hand claim I have to bet a minimum of t4000 because there is still the SB to act behind me. This is a No Limit game.


The floor rules I must bet the Big Blind as a minimum.Before I explain the logic for my argument I would like to hear some other comments please.

PS: I did place third in this MTT and I thank all of you for that. I have made 4 final tables out of 13 B&M MTTs that I have entered this year.