Except they make it quite clear where they outline what is opinion and what is fact, they don't mix the two and know when to differentiate with that. The videos in particular where they do speculate are highlighted as something they give their thoughts on, not something that is official news and facts. Plus, they do about the same amount of research we do with our characters, they talk about the details in certain pictures and videos, they talk about what it could mean, and they talk about possibilities that could become of them. For instance, take the Palutena video, that remarked on every move that Palutena did, gave their reasoning for why they felt those moves would work a certain way, but still pointed out that it's not for certain and things could be different then what they thought. That is research, that's taking time and analyzing what's been given and stating their personal hypothesis. Really, the only thing they're guilty of in that video is paying more attention to one certain angle, but even then it's not like the other angles weren't given attention, again by talking about other possibilities that could happen.
Also, what's been debunked in that video? Sceptile, while it has its faults, isn't exactly impossible and they don't place it as a frontrunner, the Gematsu leak is quite accepted in the community and, while I hate to admit it, does have its points for why it could be it (key word here being could) for the newcomers, they highlighted that Mewtwo could still happen, so on and so forth. Also, as mentioned before, none of that is given as absolute fact, but rather what they thought. So despite the faults the video has, it using outdated debates doesn't seem to be one of them.
Also, considering that they get a large viewcount from those speculation videos, I'd say that at least someone out there pays attention to their thoughts.