We journalists are sometimes accused of cultivating a guerrilla chic, chasing after guerrillas and giving them an easy deference and platform that we deny to the authorities they wish to boot from power. But this is the wrong rap. The trouble is not that we chase after guerrillas but that we don't chase after them hard enough.

We pursue them to their mountain redoubts but not to their intellectual and political roots. This is important because, notwithstanding the common myth that guerrillas are earthy folk springing from the soil of the people, their leaders customarily cross over from the educated or privileged middle class--Lenin, Mao, Castro. They are talkative types, and long before they take up guns they are making statements or being written up in publications none us us seems to read.

I write this in the grip of a rich 40-page essay, "Enemy Colleagues: A Reading of the Salvador Tragedy," by a Mexican writer and social critic named Gabriel Zaid. Appearing in the winter issue of the democratic socialist quarterly Dissent, it mines a lode of material that has appeared in the Mexican press and in some guerrilla sheets but has not been digested in either journalistic or, I gather, official analysis in this country. Three points:

1. Joaquin Villalobos, one of five guerrilla leaders who has asked President Reagan for negotiations, had a disagreement with a colleague named Roque Dalton, a poet, in 1975. Dalton himself was no innocent: he had pooh-poohed taking a "lily-white intellectual" approach to the requirements of (the Cuban ) revolution. He was, in another guerrilla group's words, ''ruthlessly murdered" by Villalobos. Later, still another guerrilla leader, a friend of the victim, acknowledged he had found it "very hard" thereafter to do business with the killer: "But the needs of our people's struggle require it. The contradictions remain secondary."

2. The reformist officers' coup of Oct. 15, 1979, was a watershed. The local Communist party, whose emphasis on the political road had cost it the allegiance of militants, felt the coup "initiated a process of change that will allow the country to emerge from the profound political, economic, and social crisis into which it has been plunged during 50 years of military governments." The Peoples' Revolutionary Army, for one, overcame its initial misgivings and quickly threw in with the "reformists and progressives."

The same Villalobos, however, at once undertook military operations against the coup. "Why did we proceed in this manner? Because the situation was a guise of imperialism to deceive the Salvadoran people: to have united behind (the coup) would have signaled a defeat, passing, if you like, but defeat nonetheless, of a revolutionary alternative . . . the necessary risks had to be taken, beginning with the loss of our cadres." In other words, Villalobos, though he agreed with the coup's program, acted to get some blood flowing and to pry the democratic left out of its initial cooperation with the junta because the wrong people were in charge.

Is there an echo, by the way, in the statement of the guerrillas in Guatemala on the recent reformist officer coup there? "The recent coup d',etat is a farce and a trick that gives the army time to breathe," they said, resuming fire.

3. All this is not irrelevant to the current talk of a negotiated settlement. The guerrillas would not accept even a junta with a program they favored in 1979. They undercut the inclination of their own political associates to favor that junta. Zaid, the Mexican writer, suggests that Villalobos is one guerrilla who is not about to accept any leadership he does not control, since "his position is vulnerable: at any moment his comrades could liquidate him politically, exposing him as Roque Dalton's assassin."

Being far from a right-wing zealot, Zaid would bring pressure to bear on both army and opposition to stop tolerating "murderers" within their ranks. He sees the purging --by amnesty and exile, not by liquidation or trial--of offenders in the army and police as the indispensable first step, since in terms of numbers of innocent deaths they bear the greatest responsibility.

Zaid would offer the guerrillas, too, amnesty and exile, seek to disconnect the political opposition from those who rejected the offer, and proceed to internationally supervised elections. His views, I have to say, throw cold water on any easy calculation that the negotiations the guerrillas demand are on.