Do atheists even need an objective moral system?

[genkaus]

You could have copied just the relevant part:

We then need to know what is good and what is bad... that was sadly missing in the long text concerning objective morality... and I didn't read it all

That's the problem. If you had read it all, you would've understood that it was all relevant. As such, you've simply focused on the narrow part and missed the analysis of the definition which went with the rest of the discussion.

Very well, I'll try to lay it out as concisely as possible.

We judge something to be right or wrong based on its consistency with a particular standard or principle, e.g. 2+2=4 is right and 2+2=5 is wrong.

Similarly, something is judged to be good or bad based on its applicability towards a particular purpose, one that may or may not be inherent to the object, e.g. a sharp knife is a good knife.

In context of human actions, morality is the standard and the values we choose are the goals. Values consistent with principles inherent to morality (such as life, freedom etc) are, therefore, right values. Actions consistent with morality and towards those right values are, therefore, right and good. The principles fundamental to any moral code, with which both your actions and your values should be consistent with, are laid out in the rest of the argument.

Let's forget the word "moral" exists, and focus on good and bad.

And how do you intend to judge good and bad without referring to morality?

Is it good to spend a day drinking in front of the tv, instead of learning something new?

Generally, no.

Is it good to kill of all those "who are currently suffering, are not contributing to the world and whose any potential contribution is easily outweighed by the drain on resources they are causing currently"?

No. Because that'd certainly contradict the principles behind morality.

What is good?
- Minimize suffering of all individuals? Even if that means increase the suffering of a few? (as in more taxes to pay for the caring of elderly and sick or wiping out these elderly and sick to decrease taxes on the remaining)
- Minimize suffering of each and every individual?
- Maximize pleasant feelings in each and every individual?
- Other?
- All of the above?

Other, as indicated above.

Intellectually, I have no answer to this.
I just spend my days doing what experience has led me into assuming that the best course of action is to disturb the minimum of people and please as many as possible, where the main recipients of such pleasing are my closest family and friends.

Specific cases of conflict not withstanding, as a norm, your chosen value is consistent with the premises of morality. What I object to is your implicit assumption that this value is inherent to the nature of morality itself.