I mean, yes, very likely. But what kind of a study is this? They surveyed a bit over 2500 users and then got results like:
13% had witnessed companies actively manipulating public opinion on the platform.
Which is arguably very difficult to detect if done well. A lot you just suspect that it has to be behind what you are reading, but it is not like someone will do a Scooby-Doo uncovering scene, ah it has always been corpo X behind this!
What they polled instead is how many users think they are able to spot something like this.
And I am not saying this to argue against companies manipulating reddit posts and comments. I'd argue the number is far higher than 10-15% of posts and this survey is not able to get to that.
Also, the survey is from 2018. It is bound to be much higher now anyways.