A percolator repeatedly moves heated liquid through a basket of grounds while brewing continues. This differs from a drip brewer's single passage into a separate carafe. The source strongly dislikes that recirculation, while also acknowledging disagreement among its readers.
For an equipment decision, focus on the implications of the mechanism. Brewing duration, heat management and the basket influence the result, and an appliance's instructions should determine suitable operation and any permitted filters. Do not add a paper filter to an unfamiliar design merely because another brewer uses one.
If you enjoy a percolator, keep a repeatable recipe and compare the actual cup with another method rather than accepting a blanket judgment. If you dislike the resulting roast intensity or harshness, a different brewing approach may better suit you. The point of understanding the mechanism is to make an informed choice, not to present one writer's strongly expressed preference as a universal law of coffee.
The conversation
A good question can make a better brew.