When religious organisations have a monopoly on charitable work people need that monopoly has bad consequences. Notably religious groups are keen to provide child care. Parents of poor families sometimes desperately need child care so they can go to work and provide for their children. Unfortunately when churches do child care religious indoctrination likely gets included. The world needs secular child care.
Dependence on religious charity
—Adam Lee writing about the United States 
|“||For whatever harm they cause, churches are often the only provider of vital services in disempowered communities, whether it's running soup kitchens, offering job-training programs, or providing space for political organizing. If the atheist movement tears down these churches' beliefs but makes no attempt to replace the services they provide, we are worse than useless.||”|
Dependence on churches for important services is bad for many reasons.
- In communities where the service provider is intolerant people belonging to different religions from the service provider may be excluded from services they badly need. People belonging to different Sects and denominations of the same religion may also be excluded.
- People may be reluctant to go to a church for help because anything connected with the Christian religion makes them feel sinful over harmless things they enjoy.
- Atheists may be forced either to do without services they need or to keep quiet about their atheism and act as if they believed. There are church groups where people can be openly atheist and get help without discrimination, at least in the UK there are. I don't know about the USA. By no means all Faith based help is given freely to Non-believers. I spent a year in a Roman Catholic convent school where I had to pretend I believed in God. That's one of the unpleasant memories of my youth.
It's important that at least some atheists work with organisations that provide services religious groups traditionally provide. If atheists are involved in helping discrimination becomes less likely. Also religious belief is declining in the west while atheism is increasing. If atheists don't take up the challenge and help with those services there may be less for everyone, believer and unbeliever alike. Ideally atheists are best working with secular charities but you know your own locality. You do well to go with what works in your area even if a tolerant religious group is involved.
If you're too busy to volunteer for secular charities yourself perhaps you can help with donations.