No suggested reviewers capability in the peer-review journal

I completely agree with ff524’s answer about avoiding fake peer review, but there’s more to it than that.

Asking an editor not to use a certain reviewer is reasonable, because there may be a conflict of interest or rivalry that the editor is not aware of but that could compromise the peer-review process. However, what’s the purpose of suggesting reviewers? That seems really biased, since presumably most authors aren’t going to suggest anyone they don’t think will like the paper.

As an editor, I’m not interested in getting reports from reviewers chosen by the authors to have a positive opinion. Instead, I’d prefer to use my own choices, and given that I’m not going to make any effort to follow the authors’ suggestions, I’d rather not see them at all.

One possibility is to avoid fake peer review:

The practice can occur when researchers submitting a paper for publication suggest reviewers, but supply contact details for them that actually route requests for review back to the researchers themselves.

See Publishing: The peer-review scam and the faked emails tag on Retraction Watch for more examples.

The option by many publishers / journals to allow authors to suggest reviewers grew, in large part, from the difficulties faced by editors in finding suitable reviewers. The online systems introduced ~10-15 years ago facilitated the ability to easily collect this information. Editors then, could potentially use the info to e.g. calibrate their own ideas on good reviewers, as well as their knowledge of people in the field.

When used ethically and properly - by authors in suggesting reviewers, and by editors making checks to ensure no conflicts-of-interest - it can be a useful tool. For example, when suggesting reviewers for my own papers, I would suggest people I didn't know personally but who were important in the field - I saw this as a way to at least (potentially) get them to read and comment on my work. As an editor, I only ever used suggestions when I had exhausted my own stock of potential reviewers (>10 refusals brings on a sinking feeling); I used them rarely as it took a lot of work to try to judge the COIs (mainly via literature and the omnipotence of Google).

The clear issues that have to be hurdled, as ever, come down to the individuals concerned. Perhaps the journal in question encountered problems over the years and rejected it as an option.