You have a point there. This is a comparison of such problem against another similar one, which has evolved more in order to draw some conclusions.
Consider that all systems of regulation (laws, morals, ethics, religion, gang rules, etc.) have the purpose of improving the survival probabilities of the group. Rules, including law, are commonly said to help keeping peace, establishing standards, maintaining order, resolving disputes, protecting liberties and rights, improving social interaction, etc., but those are just intermediary expressions of our last goal: survival. Why do we want order? Why do we want peace and not a civil war? Because as members, we want the group to continue existing and perhaps, growing.
Upon such consideration, human's tendency to survival along history has probably embedded into the kollektives Unbewusstes the notion that living is not a right but an obligation. That's why we stigmatize all things related to death: crime, suicide, illness.
It is important to remark at this point that the option is subjective (some might say that living is an obligation due to religion, others might say that we should promote and assist massive suicidal events in order to reduce world population, etc.). So, let's just consider what is happening around the globe.
Compulsory voting is a similar case, which has evolved for better in most countries. A consequence of it is that people's freedom of speech is violated, forbidding the freedom of not to speech, and moreover converting such freedom into an obligation of speech. A handicapped or sick person, who might incur into risks and large economic expenses due to the obligation to go voting, are just excluded from the decision. They are forced to do so, risking fines and even prison. Such obligation clearly violates the main goal of law.
Compulsory voting has advantages (more people gets better informed in political matters)[1]. And in order to profit of such advantages, excluded people would be considered and provided of resources and the proper conditions to vote. Only in such case, the right might be turned into an obligation. But apparently, in case of voting that's not the common case. AFAIK the tendency is to avoid the obligation and keep the right.
In case of euthanasia, the law, in practice, treats the right to live as an obligation to live, a sort of compulsory survival. The main argument is not a prohibition of suicide per se (suicide tends to be decriminalized) [2], but mostly the issues related to assisting the suicidal (helping a suicidal might be consider to be murder). Decisions are largely influenced by social audiences and political profit. E.g. when a voters majority is religious, chances are for suicide to be forbidden.
Statistics regarding legislation around the world, perhaps explained by the previous discussion of both situations, compulsory vote, and compulsory survival, show that the tendency is to respect the right and avoid turning it into an obligation.
[1] https://www.idea.int/data-tools/data/voter-turnout/compulsory-voting
[2] https://en.wikipedia.org/wiki/Suicide_legislation