From a State Department press release:
The United States Senate approved the United States-Rwanda Bilateral Investment Treaty (BIT) on September 26 by unanimous consent. The Department of State applauds the Senate’s approval of the treaty and is pleased that the Senate’s longstanding tradition of bipartisan support for these treaties has been upheld. This treaty demonstrates Rwanda’s commitment to the economic reforms that will help enable sustainable economic development and opportunity.
Since the 1994 genocide, Rwanda has made remarkable progress in implementing economic reforms that have helped rebuild the Rwandan economy and society. Rwanda has opened its economy, improved its business climate, and embraced open trade and investment policies as a means to boost economic development, job creation, and poverty alleviation.
BITs establish rules that protect the rights of U.S. investors abroad and provide market access for future U.S. investment. They also support market-based policies and best practices that treat investment in an open, transparent, and non-discriminatory way.
The Administration is also working to complete an update of the U.S. “model” BIT, which will serve as a framework for future BITs. In the meantime, the State Department and the Office of the U.S. Trade Representative, which co-lead the U.S. BIT program, continue technical talks with current negotiating partners, including key countries such as China and India. When concluded, these and other BITs can play a significant role in building strategically-important economic relationships that will support U.S. job creation, development, economic growth and competitiveness.
So unlike with FTAs, a BIT is passed in the U.S. Senate without controversy.
I feel like I just came across a paper that discussed why (many) BITs don't generate much protest, whereas FTAs do. But I can't seem to track it down. If anyone knows the paper I'm thinking of, feel free to mention it.
To some extent, the reasons for the different attitudes are obvious. Still, I'd be curious to hear those who protest FTAs explain the distinction as they see it.