I'm not a paranormal enthusiast but I have been ghost hunting about half a dozen times. I'm a very skeptical person and after ghost hunting, I'm still not a believer. I went mainly for the fun of going around creepy old buildings at night with flashlights and genuine curiosity. Heck, if you don't even look you know you won't find anything.
I can comment on the issues raised in that blog. Generally it was written in an oversimplified manner which doesn't reflect the thinking of most ghost hunters.
5. Orbs. Here, I agree completely with the blog. Just dust.
4. Thermal videos. I have no experience using this. So, no comment.
3. EVP. This gets tricky. The vast majority of EVPs are dismissable. We've caught some and I'm skeptical of any of the whispery type where you have to strain to hear anything. These are the vast majority and I think they're noise. In fact, once we had multiple recorders going and an EVP in one was identifiable as a water drop in another. That said, I have recorded 2 very clear and/or loud EVPs that have no explanation. Doesn't make them paranormal but not easily dismissable either. But, there are different levels of clarity and some would appear to rise above static. So, the blog oversimplifies by classifying them all as static. Doesn't make them paranormal but it's not all static.
2. EMF. This blog oversimplifies what ghost hunters are looking for. Yes, EMF meters detect normal EMF in a house. The stable, easy to find EMF from electrical devices. Usually stable and you can identify the source. What if there is no electrical source? EMF that varies and no source? That's different. Again, not necessarily paranormal but the source is unknown. I have used an EMF meter but have never gotten strange results on it. I've gotten readings but again I could find the manmade source in all cases. It would raise an eyebrow if I couldn't find a manmade source though. I guess the Earth can create them and that would be my next guess.
1. Eye witness testimony. Yep, agree you can't be convinced by undocumented eye witness testimony. That said, I've had a couple of strange experiences which I unfortunately couldn't document. Like I saw a stereotypical orb. I don't expect you to believe me though. And, even myself would only classify that as unknown, but not necessarily paranormal. I don't know what it was. I tried to recreate it with lights and reflections but nothing looked remotely similar. Perhaps if I had been able to photograph it and then study it in detail, I'd be able to figure out some normal explanation for it. Who knows.
I'm still skeptical and not a believer. But, I have to admit, it's kind of fun! And, you are bound to experience strange things. Most of them you can debunk with some logic and particularly if you can record/photograph/video them and analyze later. A few things remain unknown afterwards.