If you don’t have to observe the coronavirus dictates at protests, why do you have to do so at a church service. From Tyler O’Neil at pjmedia.com:

“No matter how the protests were organized and planned, the District’s (and in particular, Mayor Bowser’s) support for at least some mass gatherings undermines its contention that it has a compelling interest in capping the number of attendees at the Church’s outdoor services,” McFadden wrote.
Bowser’s COVID-19 restrictions prohibit church services with more than 100 people (originally they only allowed services with 10 people or fewer).CHBC, an 853-member church in D.C., requested permission to meet at the 45,000-plus-seat Robert F. Kennedy Stadium, which would give them ample room to social distance, but the city refused the church’s request. On September 22, CHBC filed a lawsuit and requested a temporary restraining order preventing Bowser from penalizing them for gathering.
CHBC cited the First Amendment and the Religious Freedom Restoration Act, which requires the government to meet strict scrutiny when abridging religious liberty. This means the government must prove that it has a compelling state interest and that its restrictions are the “least restrictive means” of meeting that interest.