Returning Russia to Council of Europe lacking arguments. It will be seen as a Western weakness.

Regarding the voting on the right of Russia to return to the Parliamentary Assembly of the Council of Europe (PACE) and the European Court for Human Rights.

1. The argument of "return to dialogue with Russia" by Germany and France is severely lacking because:

A. Russia does not recognize that it has annexed Crimea through an armed "referendum", ie on the basis of an occupation, even if followed by a "referendum." Such armed referendums are illegal, a fact neglected by Russia, which in all other international disputes invokes the international law, yet not in this case convenient to Russia. The referendum was, however, illegal under international law, which is contrary to the concept of a rule of law invoked by Russia, local or international.

B. Also, despite the "Minsk" dialogue on Donbas/Eastern Ukraine, Russia continues to occupy Donbass and provide weapons and send troops to the region, controlling the area directly from the Kremlin (Surkov etc) and, obviously, refusing to recognize it - thus refusing dialogue.

C. Also, the dialogue on the latest events /confrontation on Georgia is absent and only threats are heard, which is contrary to the idea of ​​a return to dialogue.

D. Negotiations on the Transnistrian issue in the Republic of Moldova, even in spite of the previous Government concessions on registering the "separatist" cars with "neutral" (no Moldovan flag / marking) car plates and thus offering transport opportunities for Russian investors in the Transnistrian region, are de facto blocked by Russia. Mimicking dialogue, through the presence and direction of proxy "separatists", does not demonstrate the desire for resolutions or dialogue.

E. Russia did not modify its foreign policy and military concepts that allows it unilateral, unsanctioned by UN, intervention. 

2. The argument of Russia opening was overturned immediately after that vote by statements by Russian officials that any subsequent "threat" would have repercussions. This demonstrates not only the refusal to dialogue - rather a continued belligerent policy internally and externally. Apparently  the vote seems to have encouraged Russia and did not open it for dialogue. Taking into account that in International Relations both power politic dynamics and local "individual" factors influence the perceptions of the decision-makers, the CoE vote can be seen by the Kremlin not only as a gain. It can also be seen as a proof of what Russian leaders often propagate as a "decadence" and "weakness" of the West. The vision of "weakness" is completely neglected by the West, which in its own complacency neglects this Russian element in international relations, which is wrong, as reality proves. The same logic is applicable by Kremlin towards the individual voters (national political players) of the resolution.

3. The argument of Russia's return to the European Court of Human Rights (ECtHR) seems to severely lack the factual situation - this argument suggests that such a return gives a certain percentage of ordinary Russians higher chances to benefit from ECtHR decisions - yet misses the fact that Russia has already adopted national legislation (!) through which it can neglect ECtHR decisions. Thus, this argument in favor of the vote was null ab initio. One should consider that the Kremlin will allow some minor" cases into ECtHR, without a too serious of an impact on general civic freedoms in Russia, to "demonstrate" a so-called "factual democratic attitude." Those who follow the subject understand that such unrepresentative cases are maintained, especially in relatively small numbers compared to the total number of issues, to use them against external critics, but without real impact on human rights at home, followed by "whataboutism" (diverting attention to "what about you violating the rights of... - an argumentation allowing the person/state continue violations, based on mistakes or illegal actions of others - basically, I am equal to "you", so if you stole or destroyed something, why can't I, nevermind the legal implications).

Another argument noted by Alina Polyakova in FT (if I am not mistaken) is the precedent of Russian exclusion for other cases - as, for example, this situation is closely followed by Turkey, with a high number of cases. However, if a country is to self-exclude from ECtHR, just as Russia self-excluded itself from other (military) treaties, due to violating them when those didn't fit its purposes, and blamed the West for it, this argument would not stand in all such cases.

(in absence of time, the only link I am providing is the one on Russian decision to overrule ECtHR decisions - see below)
https://www.bbc.com/news/world-europe-35007059