It can happen to anyone and cause a reputational risk. Once upon a time $workplace had a Zoho Form that would be blacklisted by Google Safe Browsing or Microsoft Edge for arbitrary periods of time, presumably because someone used Zoho to make a phishing site, leading to some very confused calls.
Sounds a very convenient mistake to do on your competitors? It does not sound believable that they would not know what zoho was or that it makes no sense to flag all the zoho domain.