OK, most religions make you do things which are fairly stupid but not onerous:
I think that in order to intelligently condemn some of these practices as 'stupid', one would first need to understand their contexts and motivations.
Buddists: Meditation, insects.
Meditation basically means mind-training. It fosters the awareness of and the ability to consciously control one's own mental states. In Buddhism there are two basic kinds of meditation (which in turn have countless variants). One of them is called 'Samatha'. It isn't unique to Buddhism and is found in many sorts of Indian yoga. It's basically training in concentration, in focusing on a chosen object in such a way that the mind doesn't jump around crazily as it so often does. The other kind of meditation is called 'Vipassana' and it is more specific to Buddhism. This kind of meditation is often called 'mindfulness' and it's basically just a process of non-judgemental observation of how one's own mental states evolve. One observes the arising and subsiding of functional and disfunctional states, such that one can gently intervene so as to head off disfunctional states and foster functional ones.
Non-Buddhists might choose to dismiss these practices as 'trivial' or 'stupid', but they are central and fundamental to what most varieties of Buddhism are trying to accomplish.
I'm not sure what you mean by 'insects'. There are prohibitions in the Vinaya (the Buddhist monastic rule) about gratuitiously killing small sentient beings like insects. That's a basic ethical practice, fundamentally associated both with compassion and with feelings of fellowship with all of sentient life.
There are lots of other rules in the Vinaya that you could have mentioned that probably do seem 'trivial' to outsiders. There are rules about how one's monastic robe should be worn, even rules about how to chew one's food. In a way, these things are trivial to Buddhists too. So why are they there? It gets back to mindfulness. These are monks that we are talking about, not laypeople, and the Buddhist monastic rules are conceived as 'rules of training'. They are intended to make the monks focus on the small details of what they are doing, in such a way as to be fully aware and present in the moment.
Jaines (don't know what they are): Insects, plants, speech.
Jains are an ancient Indian religion that may be older than both Hinduism and Buddhism. It still exists today and there are maybe 4-5 million Jains in India. (Not only in India, there's a big Jain temple here in Silicon Valley).
Outwardly, Jains appear very similar to Buddhists. They have monastics who wear similar robes and have shaven heads. Both Buddhism and Jainism don't revolve around a central 'God'-concept. Maybe the most obvious doctrinal difference is that the Jains believe in the existence of souls while the Buddhists don't. (I should add that ancient and medieval Jain philosophers developed some very interesting logical ideas that contemporary Western logicians are just begnning to fully appreciate.)
Jain monastic practice is similar to Buddhist monastic practice, albeit a little more extreme. The Jains do tend to avoid agricultural occupations for fear that their work might kill small beings in the soil. That led the Jain community in India to focus on urban occupations like trade, resulting in the Jain community being quite prosperous today.
You mentioned 'speech'. Both the Buddhists and the Jains place considerable emphasis on 'right speech'. 'Right speech' starts with honesty, with telling the truth and avoiding lies. It progresses to avoiding hostile and divisive speech. That doesn't mean that Jains and Buddhists have to agree with whatever other people say. It just means that they should express their disagreements in a friendly and compassionate manner. They should try to avoid generating unnecessary animosity. They mustn't let themselves get caught up in childish ego-contests.
That's not the least bit trivial or stupid. On one level it's basic rhetoric. If person A disagrees with person B, person A isn't going to win person B's agreement by insulting him or by putting him down. What person A needs to do is make person B want to agree. That's how persuasion works. Turning disagreements into ego-contests almost guarantees that agreement will never happen.
And from the Buddhist and Jain perspective it reaches a lot deeper than mere rhetoric, it's part of one's own inner-work. That's because the kind of ego-involvement that leads a person into flame-battles is also what leads to the arising of disfunctional psychological states and the suffering whose elimination is the ultimate goal.
