not to justify the drone killings, but those are strictly political with stated political goals – kill those who seek to destroy and destabilize the US – rather than arbitrary ideological/religious killings such as the Charlie Hebdo ones. political goals tend to be more justifiable and legitimate. (I'm not taking a stand, I'm just describing the difference between state sanctioned political violence and violence committed by non-state entities).
in classical IR theory, sovereign governments have a monopoly on force and the duty to protect their citizens. the US is doing it in a historically atypical way, due to the preemptive and asymmetric nature of the strikes, but I'd argue that a drone strike is no different in justifiability than a conventional bombing or an attack by ground troops.
the US and CIA has decided that drone strikes are the most efficient and safe manner of furthering their interests – stopping terrorist groups that Pakistan clearly allows to exist. Pakistan has failed at policing their borders and since the groups that have formed in this power vacuum threaten the US they have succumbed their sovereignty.
the drone strikes aren't merely arbitrary. the people targeted are considered to be terrorists or combatants against the US. it's pretty simple really. the US wouldn't risk such a massive backlash in order to assassinate everyday people. yes there is collateral damage, but that is the nature of war. if you compare drone strikes to conventional ground troop and artillery combat, intelligence-supported drone strikes are generally more effective at hitting the intended. if you're going to call the drone strikes murder then you can go ahead and call every person that has ever died in a war 'murder'.
you may be interested to know that
A February 2012 Associated Press investigation found that militants were the main victims of drone strikes in North Waziristan contrary to the "widespread perception in Pakistan that civilians... are the principal victims."
additionally,
The CIA reportedly passed up three chances to kill militant leaders, including Sirajuddin Haqqani, with drone missiles in 2010 because women and children were nearby.
believe it or not, family members of people killed by drones tend to insist that their relatives were entirely peaceful.
the drone strikes are targeted, not meant to incite terror, aimed at specific combatants, and conducted with political goals in mind. this differs entirely from terrorist attacks which are indiscriminate, designed to create terror, and ideological in nature. hence comparing the two is useless.
you may not agree with this but states possessing a monopoly on the use of force is the predominant narrative that underpins modern realist state theory. other countries would do the same, it's just that the US has an unparalleled power projection ability.
in general, we have different standards of acceptability of the killing of a human depending on the context. it's a bit idealistic to call every death inflicted by humans 'murder' – deaths in a (just) war are regrettable but often unavoidable.
it's not really useful to decry all political deaths. and it's not convincing to hold up deaths from drone strikes as somehow equal in moral repugnance to terrorist attacks. admittedly the term 'terrorist' is a charged and not entirely useful term.
if you are seeking to score a victory against the supposed hypocrisy of the US in permitting the drone strikes, you have another thing coming. I don't really agree with the effectiveness of the drone policy but I am irked when people describe drone strikes committed by the US as an example of their moral failings.