I use bolts and autos for calling. I've been using ARs for calling since the mid 80s and started building versions specifically for hunting shortly after. I remember and still use a couple of the first flat top models that were simply an A2 with the handle chopped and a Weaver rail bolted on where the handle was. As good as they are for the task there isn't any doubt guys were using them much earlier. As far as becoming "fashionable", some less knowing would claim they still aren't. lol! I'd say they became more popular for calling in the mid 90s. At least as far as internet callers go.
When I first started frequenting the pred boards I remember only a couple guys that used ARs for calling. But then, just as now, the boards only represented a fraction of the callers out there. Back then usually even the mention of using an AR for calling brought criticism from the majority of members. The goal then and now is to take the animal with one shot. Since a good AR is at least as accurate or more than a bolt, it is a good choice for calling and comes in handy when multiples show or the rare instance a second shot is needed. Most guys are pretty accepting of ARs now and don't make the uneducated "spray and pray" comments they used to make.
Then there are those still proclaiming it's their way or the highway, suffering from a bad case of Zumboitis. Usually it's the same guys that whine about use of e-calls and were still in pampers when a large percentage of guys were calling. lol!
Just like with calling, many of us have been using them long before the "movie stars" took up the habit. Many callers have no desire to ever use one and I understand and respect that decision. However as much as I love using bolts in addition to ARs, I feel anybody that can't admit that ARs are a very effective calling rifle is in a serious state of denial. I'd never criticize anyone for doing so. When I see someone do it, they appear very short sighted.
Good hunting