What is the problem of Trump Jr meeting with Russians?  Here is a list of Democrats who met with Russian Ambassador Kislyak: 
1. Senior Obama advisor John Holdren
2. Senator Claire McCaskill
3. Senator Sheldon Whitehouse
4. Former Senator Mary Landrieu 
5.Senator Amy Klobuchar
6. Senator Dianne Feinstein 
7. Senator Jack Reed
8. Senator Bob Casey 
9. Senator Maria Cantwell
10. House Minority Leader Nancy Pelosi
During President Trump’s first address to Congress, Ambassador Kislyak was the guest of Democrats and sat with them during the address. 
According to official visitor logs, Kislyak visited the White House 22 times during President Obama's tenure.
And let us not forget Senate Minority Leader Chuck Schumer being photographed with Russian President Vladimir Putin. 
Collusion?  Of course not.  Democrats would never do that.