If it is said that seminal energy brings strength, power, and peace, then how are so many Asura and rakshas powerful if they don't practice celibacy? (Sometimes even more powerful than god)
Asuras were/are never powerful than God. Your question is wrong. I disagree with you for calling their RAGE/ ANGER/ TYRANNY and MASS POLYGAMOUS & formchsnging population as "Powerful". PUT TO TRIAL on Earth They were powerful in their region & reign period only because they constructed their region & mated to give their offsprings genes as their subordinates/ slaves (in otherwords populous polygamy) to multiply bonded labour.
ASURAs lack Power to energise humans
The attrocities they committed panickked others to such extent that all were afraid of asuras. None of asuras could make living of humans/ sages peaceful. Power of asuras is miniscule. Even a human can become asura by bad deeds.
We have 2000 millenium example of attackers targetters or terrific terror etc. Such humans are of asura nature. DEMON: DARPASHIRA (fickle headed) Asuras are DEMONs who may not know discretionary powers even if they copy rules & regulations from the good. They may only try to spoil the good because they cant follow good rules of harmony.
"Sahaadevan was good but Duryodhana who approached him was not good. Vibheeshana was good but Raavanasura was not good". ASURA : FATE Hence, though rules of life are there for humans Asuras never obeyed them as they had multiple forms from bad spirits.