Why is it so easy for the United States to send money to other countries but it takes weeks/months to send out stimulus checks to Americans?

Fewer recipients.  When we send to other countries, we send to their government or to some other organization, but it's only a few checks that we send -- and they have to handle the distribution to millions.  With stimulus checks, we have to send millions of payments ourselves.

America is securing there resource / economic interests overseas... People in America are not that important qualifying for the stimulus

the US government does not have a list of every American

Priorities, man. 

This aid is included in budgets as just a small part and the whole thing take months to get through all the stages before it is passed in the House and Senate.

You should read up on how laws and budgets are arrived at.  Or you could watch The West Wing, then you would learn far more about how your government operate whatever party is in power.

A half dozen wire transfers for millions of dollars vs 200+ million wires, checks, debit cards for billions of dollars.

It also took over 100 years, and constitutionalist Trump, for the new age government to give its citizens any monetary charity. 

Yes. The defense budget was pretty high.

you don't matter...

Because, Republicans.