Hi,
We've had a bit of a disagreement about a sentence and the correct grammar for it. I will give you the sentence below, in context, bolding the sentence.
Social Media is shaking up the marketing world.
Traditionally, marketers broadcast messages out to consumers and tightly controlled how brands were perceived. The social media landscape has shifted the control of your brand from your marketing team to your customers themselves.
The bolded sentence doesn't sound right to me. I did some research and thought that it was "past perfect" (an action that happened in the past and has been completed) meaning that it would need to read "...marketers have broadcast...".
The argument against me is that we are not speaking in that tense and it is correct. A third party says that it does not read well regardless and should be changed whether it is correct or not.
Could a grammar expert please mediate?

Thanks so much!