People say that in marketing, it is bad to be negative, trashing the competition's product and/or business. I can see how that makes sense in public advertising. Being the angry company who keeps on kicking others will not help build your brand in the long term.
In closed room sales and investor pitches, I think it is a bit different. You don't have much time, and the audience across the table might not know the market very well. Stressing your positives and hoping that they will fill in the comparison to the competition might not be enough.
The tone of a presentation does not have to be negative, the differentiation versus the competition should be made very clear. In most cases, there is a positive way to spin this story. Both models have a reason to exist: your product works great for this segment, the other product will work better in that segment.
Even in the consumer market, people are looking for the head on comparisons, even if they are absent in advertising. Product reviews by trusted sources, and online comments by honest consumers, trolls, and competitors impersonating as a reviewer will inform the buying decisions.
For corporate buyers or investors, this back channel to get the real story does not really exist, and/or they do not have the time to find it, so being a bit more explicit might not be that bad.