This is the question that some people have. Should you still buy software if it uses scare tactics to get you to buy it? In my opinion, it all depends.
I can understand the side that argues you shouldn't. If they are lying to you to get you to buy their software, how can you trust that their software is any good? What if you need to contact them for support? Etc. Those are all very valid points.
However, there are a few things to keep in mind. What if the company that is selling the software is not the same company that created the software? In that case, even if the company that is selling it is horrible, the company that created it may have done a good job with creating the software itself. Also, what if the software is good and you have no need to ever contact support and deal with the company themselves? These are all points that should be considered.
This is why I go back to saying it all depends. Although a company using scare tactics may be a sign that you shouldn't trust their software, you shouldn't rule out trying their software for that reason alone. Try the software itself and factor it all in before making a choice on if you should buy the software or not. And you may also want to check EasyTechReviews.com for a review. It could be on there. ;)