rent control may not equate to low income housing.  the "move in costs" may be the only collateral owners have with a tenant.   should the tenant decide to not pay rent and become a squatter, there is at least some income for the owner to cover the  cost of not having a paying tenat. 
 as to the security deposit - everything is incredible expensive. a tenant of ours ruined an almost brand new medicine cabinet  - no biggie -the security deposit would surely cover it,. it cost twice as much as it had! we wound up paying the amount over what his deposit had been.  and we doubled what we ask for a deposit. when all added it up, it is a lot of money. we've worked with people to do installment payments because the amount is so high. never asked anyone to do 3x the rent - excessive.