Ramsdale played in all 38 of the Gunners' league games last season.
"I haven't had a single question on why Gabriel Jesus hasn't started and he's won more trophies than anyone, including me, in that dressing room.
"I cannot have two players like this in one position and not play them. David has tremendous qualities like Aaron has, like Karl [Hein] has, but we have to use them you know."
Arsenal will make their first Champions League appearance since the 2016-17 season against PSV Eindhoven on Wednesday before playing Tottenham in Sunday's north London derby.
Arteta suggested he will continue to rotate Ramsdale and Spain's Raya and added there had been previous occasions during his Arsenal tenure when he wanted to switch goalkeepers mid-match.
"I didn't have the courage to do it. But I'm able to take a winger, or a striker, or a central defender or to drop to a five and hold that result," Arteta said.
"We drew those games and I was so unhappy.
"Why? Why not? [change the keeper]. We have all the qualities in another goalkeeper to do something when something is happening and you want to change momentum. Do it. Now my feeling is to get everybody engaged in the team. They have to play, regardless of the competition. We have to do it."
'Too early to understand Arteta's decision'
Ex-Manchester City and QPR defender Nedum Onuoha said it is "too early" to understand Arteta's decision to swap in Raya for Ramsdale.
"I was surprised and I did feel a bit for Ramsdale," Onuoha told the Football Daily podcast.
"It is too early to understand the why because I need to see who he is going to pick midweek in the Champions League, who he is going to pick for the game against Spurs and whether this is going to be for a prolonged period or whether it's going to be a week-by-week basis which I don't think would benefit either of them."
Former Tottenham and Fulham full-back Stephen Kelly added: "As a defender I don't think you are worried about it if the player coming in is as equal or as good as the player going out. That's the difference.
"We've been in teams where there is a certain number one and a certain number two. When the number two came in, you wouldn't be worried about them but you would need to protect them a bit more.
"This is like for like. You are not changing anything when it comes to quality."
On Ramsdale's response to being dropped, Arsenal captain Martin Odegaard said: "I think he will just keep working hard, like he is always doing.
"He was there supporting us, cheering for us, helping us. He is a great character and he showed a very good response today by backing his team-mates, being there and giving us energy.
"We have two good goalkeepers there and it's big competition.
"We are lucky to have two such good goalkeepers and we will see who will play, but both of them are excellent."
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