Allowing parents to file joint tax returns with the children that still live with them due to financial difficulties

I am a single mom - I own my home, and have 2 children that still live with me due to financial hardships - neither one makes enough to move out and pay their student loans and other obligations - however since they are over 24yrs I cannot claim them as dependents even though I support more than 50pct of their expenses, and I loose my status as head of household - how is this fair or right - Many families have had to join together due to loss of job and have moved back with their parents,l to make ends meet and the parents are the sole support they should be able to claim them as some sort of dependent since they are paying all the household expenses. My status of Head of Household is in fact the case, but now they tell me I am single.