For those new gamblers that are that seeing those bad reviews and issues then its true that competitors might be that trying out to destroy other competitions out there and thats why verifying out those issues will be that needed and not just that drawing up some conclusions just because you have seen 1 issues on which you dont even know if its real or just simply trolling or doesnt show off any solid evidences. You can always ask out the community into this forum about such manner.
That is why it is better to check other sources for reviews of a gambling website. Some bad reviews online are fake or people are being paid to make such bad comments. If that gambling website has a thread here, asking forum members for feedback could really help. Reviews from users here are more reliable.
Personally, I never trust those review websites. What I always do is I make an account on that gambling website and check if the reviews were really true.
Honestly I'd rather go on forums than trying to believe on the words posted on a reviewing sites. Since there we could really see the real sentiments of people using their casinos.
Since as you said there's possibilities that there are some external forces would post something against them to try to destroy their reputation. That's why its good to see an alternative source of information especially in this forum since for sure that we can get legitimate reviews coming from real reputable people.