After a hearing in the Senate on Friday, it was House Democrats' turn Monday to excoriate Postmaster General Louis DeJoy over changes he's been implementing at the U.S. Postal Service.

Similar complaints were echoing in the streets over the weekend, as more than 800 postal protests were organized nationwide, with more than 40 in Massachusetts. Concerns about postal service slowdowns and possible voter suppression appear to have motivated some unlikely activists.

At a rally near the main branch of the Arlington post office Saturday, many participants told WGBH News this was the first demonstration they’d ever been to.

“It’s our first time at a rally," said Arlington resident Judi Gardner, who came with her 84-year-old mother Kay Gardner. “We’re here because my brother’s a postal worker. I love my mail carrier, very reliable. On the hot days I have water for him, freeze pops.”

Professional oboist Rob Sheena of Lexington turned out on Saturday in spite of DeJoy’s pledge last week to fix service disruptions and keep the Postal Service neutral in November. Sheena told WGBH News he wasn’t sure whether rallies like the one he was attending would have an impact, but he still felt obligated to stand up.

“I don’t know if it’s going to make a difference, but I don’t know what else to do,” said Sheena. “I think all we can do is make what I’d have to describe as a full court press on this.”

Arlington resident Julia Bloom also said she had little experience with protests. But with a seemingly nonpartisan institution like the Postal Service being politicized, she said she was spurred to action. "It feels like in the last few years, a lot of things that were apolitical have become political. Even my face mask is political now."

DeJoy has come under fire for a number of changes he’s made in his two months leading the U.S. Postal Service, including the removal of hundreds of sorting machines. The postmaster general has reversed course on some reforms that he says were designed to cut costs, pledging last week to put them off until after the presidential election. But he said Monday there would be no effort to reinstall sorting machines that have already been removed.