IT IS a reproach to the Iranian terrorists that for 163 days they did not allow the totally non-political International Committee of the Red Cross to visit the embassy prisoners. Previously, the terrorists had allowed visits only by the likes of politically malleable American ministers whose reports did not enjoy broad confidence. The captors presumably changed their line and let in the respected all-Swiss ICRC not out of any humanitarian instinct but to determine the Carter administration's redoubled effort to put an international squeeze on Iran.

As it was, however, the Iranians refused to allow the ICRC to follow its usual practice, one instituted in order to lend extra credibility to ICRC observations, of interviewing prisoners in privacy. The former shah, when he allowed the ICRC to inspect his political prisons on three occasions in 1977-78, was not afraid to permit the organization this sort of unintimidated access to "most" of the 5,000 prisoners interviewed, the ICRC subsequently reported. The new crowd allowed private access to none. Is it not interesting that, by this one telling indicator of respect for accepted international standards of decency, the revolutionaries at the embassy are not doing as well as the former shah?

The ICRC visit did apparently produce the best evidence so far available that all the missing Americans are accounted for and that their general condition -- the ICRC is to make individual reports to the families -- is "O.K." But the ICRC visit produced no signs of a commitment either to permit regular further visits to the hostages or to release them. This is the crux of the matter. A limited one-shot gesture to international opinion -- a bow made only after 163 days of calculated defiance -- will be seen on all sides as an act of pure cynicism if it is not followed up at once. Certainly this one visit provides no grounds at all for the United States and others to hold back their efforts to make Iran free the hostages.