Its a fine route if its one* way of being recruited. If it is the only* way then I really wouldn’t agree.It’s quite a big talent pool though! Being a graduate in full time work doesn’t preclude you from doing a vac scheme in all cases (as I can personally attest to), nor does being an international student.
It obviously sucks when your opportunities are reduced by virtue of the fact that you can’t do a vac scheme but it’s a perfectly rational position for a firm to take when all methods of recruitment have various pros and cons to be balanced
Being in full-time employment precludes many many people from doing a vac scheme. Taking 2-3 weeks off to do a paid internship with another employer may not fly over well with most* bosses. All after you've taken day(s) off to interview and attend assessment centers as well. Not to mention you are literally not guaranteed a job, so you risk using all you annual leave and/or getting fired without a guarantee for employment.
It’s unacceptable for a firm to preach social mobility and DEI while this is their only* recruitment method.