American television news outlets reporting on Syria echo the Obama administration's views on Russian bombing of rebel groups; generally the perspective offered is that the Russians are doing something wrong because they are not targeting ISIS enough (or at all).
One prominent and representative example involves air strikes on the town of Talbiseh. For example, Buzzfeed reports:
"The areas targeted were mostly strongholds of Jaish al-Fatah, a coalition of rebel groups that includes the Al Qaeda-linked Jabhat al-Nusra, but also the popular Ahrar al-Sham, a hardline Islamist rebel group backed by Turkey and Qatar. All the targets were far to the west of ISIS strongholds in eastern and northeastern Syria, but key to protecting Assad's dominion in the country's northwest and the capital, Damascus."
Accordingly to the Washington think-tank Bipartisan Policy Center,
"While the roughly dozen member groups are typically dynamic, three are of particular note due to their size and affiliation. The al-Nusra front, which contains approximately one third of Jaish al-Fatah’s active fighters, is explicitly allied with al-Qaeda, and has also recently demonstrated opposition to the U.S.-Turkish alliance against ISIS, which al-Nusra leaders claim focuses too little on evicting Assad. Secondly, Ahrar ash-Sham contributes roughly another third of fighters, many of whom are practicing Salafis and sent condolences to Taliban leader Mullah Omar’s supporters upon news of his death. Further, Jund al-Aqsa, another important group within the umbrella, is known to be a strong al-Qaeda front organization. Most of the individual groups within Jaish al-Fatah are jihadist in nature, and advertise their battles as part of a larger jihad for a repressive form of Islamic governance."
http://bipartisanpolicy.org/blog/fight-against-isis.-jaish-al-fatah
So, while the Russians may not be focusing on ISIS, it appears that at least some of their targets are radical Islamic militants affiliated with or sympathetic to terrorist groups like al Qaeda.
The air strikes by the Russians are taking place in areas bordering regime held territory, which might be viewed as on the front line of rebel initiatives against the national government.
For the record, I do not support either American or Russian bombing in Syria. Bombing of ISIS positions in the north cannot deprive ISIS of a stronghold; only ground troops can dig ISIS fighters out of their occupied, fortified positions and kill or capture them. Bombs are by nature indiscriminate, destroying whatever is within their blast radius, which in urban areas inevitably includes civilian residents and infrastructure. By creating a new generation of victims, the U.S. guarantees fresh recruits, supporters, and sympathizers for ISIS and other anti-western militants and terrorists.
If the goal is the overthrow of the Assad regime, a better strategy would have been to create a no-fly zone: without air support the military balance would quickly shift in favor of the rebels. Of course, this might well mean the establishment of radical Islamic government, as the Russians suggest, as well as continued civil war as the patchwork of Islamic militant groups battle one another for domination.
Al Qaeda targets the "far enemy" meaning the West. By contrast, ISIS is firstly concerned with the "near enemy" meaning Shiite Muslims and Arab monarchies in the region. ISIS didn't start beheading Westerners until after it was targeted by the U.S. led coalition; calls for lone wolf attacks also came later.
Frankly, I don't understand why the United States doesn't allow Iran to have the headache of prolonged unconventional warfare with terrorist reprisals on behalf of its client states, Iraq and Syria. Syria has been in the Russian/Soviet orbit for decades and has been supported by Iran since its Islamic revolution. The idea that the U.S. can establish regional influence through Syria is preposterous. As for Iraq, its Shiite leaders spent years in exile in Iran, and because of deep religious and political ties have been firmly in Iran's orbit since they came to political power in Iraq last decade.
The Syrian air force has been far more active than the Russians. From late 2014 to mid-,2015 they carried out more than 28,000 air strikes against rebels. Many used helicopters to drop barrel bombs, but there were many air strikes using Russian fighter jets sold to Syria long before the Russians' more active recent intervention.
The primary accomplishment of the new intervention is to make a no-fly zone impractical, both because of updated air defenses and because of the presence of Russian pilots, since unlike Syria, Russia is a nuclear power and overt military attacks on its military are not lightly undertaken.